Chemistry

Sample Paper – 2011
Class – XII
 Subject -
Chemistry (Theory)
TIME : 3 Hours                                                                                                                  M.M. 70
General instructions :-
1.      All questions are compulsory
2.      Internal choices has  been provided in some questions you have to attempt only one of the choice in such questions.
3.      Q.No 1 to 8 are very short answer type questions, carrying one mark each.
4.      Q. No. 9 to 18 are short answer type questions, carrying two mark each.
5.      Q.No. 19 to 27 are also short answer questions, carrying three mark each.
6.      Q.No. 28 to 30 are long answer type questions, carrying five mark each.
7.      Use of calculators is not permitted. However you may use log tables, if necessary.

Q.1 What is an azeotrope?
Q.2 People living at high altitude generally suffer from anoxia , Explain.
Q.3 Define limiting molar conductivity .
Q.4 “A greater insight in to the energetic and mechanistic aspects of reactions”. Explain the above statement which was given by “Max Trautz” and William Lewis”
Q.5 Define the term mutarotation
Q.6 Name one Biodegradable aliphatic polyester.
Q.7 Ortho-sulphobenzimide is used in the preparation of sweet for a diabetic person or patient, why ?
Q.8 How does prevailing temperature influence the extent of adsorption of a gas on solid.
Q.9 What do you mean by activity and selectivity of catalysts?
Q.10 What are the units of molar conductivity?
Q.11 Mention the factors which affect the rate of a chemical reaction.
Q.12 How will you convert –1. Toluene to benzyl alcohol 2. But –1-ene to  But -2-ene. 


Q.13 Give IUPAC names of following
                             OCH2 COOH
         II
 
  [1]                                                                   [2]     CI3 – C – CH2 Cl
-Cl
 
                                                                                            O
Q.14 Halo arenes are less reactive towards electrophile than benzene.
         OR
Halo alkanes have higher boiling point than the corresponding parent alkane.
.15 Give IUPAC names of following.


  1. o- BrC6H4 CH( CH3) CH2 CH3
  2. m - Cl C6H4 CH2C (CH3)3


Q.16 How do you explain amphoteric behaviour of amino acids?
Q.17 Define thermoplastic and thermosetting plastic (polymers) with two examples of each.
Q.18 How do antiseptics differ from disinfectants? Give one example of each.
Q.19 What are biodegradable and non-biodegradable detergents? Give one example of each.
  1. Q.20 How are peptides formed. Show the formation of a peptide bond with the help of a diagram.
                                                                            OR
         Write short note on- 1. Glycosidic linkage 2. Invert sugar 3. Anomers
Q.21 How will you bring about the following conversions –
         [1] Aniline a) Chloro benzene [2] 2-Chloro butane to 3,4- dimethylhexane [3] 1-Bromo propane to 2-Bromo propane
Q.22 [1] Alcohols are comparatively  more soluble in water than Hydrocarbons of comparable molecular masses, explain.
         [2] Write the reactions of WILLIAMSONS Synthesis of  2-Ethoxy 3-Methyl pentane starting from ethanol and 3- methyl pentan-2-Ol.
Q.23 The density of an atom is 7.2g cm–3. It has bcc structure. The edge length is 288pm. How many atoms of element does 208g of element has?
Q.24 Define Osmotic Pressure. Arrange the following in increasing order of OP:
      1. 34.2 g/L of sucrose (M M = 342)   2. 60 g/L Urea (MM = 60)          3. 90 g/L glucose (MM = 180)
Q.25 Calculate standard free energy change for the following chemical reaction –


20070709251962001183979159%20_image079
20070709251962001183979159%20_image081
Q.26 Explain following –
         1. Activation Energy   2. Threshold Energy   3. Activated complex.
Q.27 "Action of soap is due to emulsification and micelle formation".Comment.
Q.28 What are the Colligative properties? Explain any one of them. Show that elevation in boiling point is a Colligative property.                                                            OR    
 The following results have been obtained during the kinetic studies of the reaction-
         Experiment      [A]  Mol L-1                      [B] Mol L-1                        Rate [ mole L-1 min-1]
         I                          01                                            01                          6.0 x 10-3 mol L-1 min-1
         II                         0.3                                           0.2                         7.2 x 10-2 mol L-1 min-1
         III                       0.3                                           0.4                         2.88 x10-1 mol L-1 min-1
         IV                       0.4                                           0.1                         2.4 x 10-2 mol L-1 min-1
          Determine the rate law and the rate constant for the reaction.
Q.29 [a] Write mechanism of acid dehydration of ethanol to yield ethene.
         [b] Explain – 1. KOLBE  REACTION   2. REIEMER – TIEMANN RACTION.
         OR
            Explain – 1. Swarts reaction. 2. Diazotisation reaction  3. Zaitsev rule.  4. Sand Meyer reaction
5. Friediel craft’s acylation reaction of chloro benzene
Q.30 a. What is the difference between Reducing and non-reducing sugars or carbohydrates?
         b. Differentiate between globular and fibrous proteins.
         c. What are Enzymes ?OR
         Define –
         1. Chemotheraphy   2. Antacids   3. Food preservatives  4. Broad spectrum antibiotics .5 Drug Target.
***



Sample Paper – 2011
Class – XII
 Subject -
Chemistry


Time : 3 Hrs.                                                                                                  MM : 70

            General Instructions :
            1.         All questions are compulsory.
            2.         Questions no. 1 to 8 are very short answer questions and carry 1 mark each.
            3.         Questions no. 9 to 18 are short answer questions and carry 2 marks each.
            4.         Questions no. 19 to 27 are also short answer questions and carry 3 marks each.
            5.         Questions no. 28 to 30 are long answer questions and carry 5 marks each.
            6.         Use log tables if necessary, use of calculators is not allowed.

1.         Why LiCl acquires pink colour when heated in Li vapours ?                                     1
2.         Under what condition  a positive deviation from Raoult’s law will be shown ?       1        
3.         Why heat of chemisorption is always more than that of physisorption ?                   1
4.         What is the significance of leaching in the extraction of aluminium ?                       1
5.         Write down the IUPAC name of :                                                                             1  
                       
CH3––CH═C—CH—CH3
                          
               H3C     Br
                                                                     ‌ ‌             
6.         Give the IUPAC name of the following :                                                                  1
                                                           
                                                                     I
                                                             
                                                                                   CHO
                                                                                 


7.         Differentiate between chirality and chiral centre                                                       1
8.         Why is NH3 the strongest base amongst all the hydrides of group 15  members?     1
9.         Calculate the freezing point of a one molar aqueous solution of KCl.
            [ Density of the solution = 1.04 g/cc. , Kf = 1.86 K Kg mol-1 , At wt. of K = 39 and
Cl = 35.5]                                                                                                                    2
10.       (i) For the assumed reaction, X2 + 2Y2    2XY2 , write the rate equation in terms of  rate 
                 of disappearance of Y2 .
            (ii) Identify the reaction order if the unit of the rate constant is sec-1.                       2
11.       State what are :                                                                                                           2
            (i) Hypotonic solution ?
            (ii) Azeotropes ?
12.       State :                                                                                                                          2
            (a) One limitation of Ellingham diagram.
            (b) The principle of zone refining.     
13.       Write balanced equations (only) for :                                                                         2
            (i) Hydroboration-oxidation reaction.
            (ii) Reaction of  phenol with CCl4 in the presence of NaOH.
14.       How would you account for the following :                                                              2
            (i) Phenols are stronger acids than alcohols.
            (ii) Ethers are much lower boiling than the alcohols of comparable molar masses.
OR
Explain how an –OH group attached to a carbon atom in the benzene ring activates it towards electrophilic substitution.                                                                           
15.       Alkylamines are stronger bases than arylamines. Why ?                                            2
16.       Write equations  only corresponding to the following reactions :                              2
            (a) Carbylamine reaction
            (b) Diazotisation.
17.       (a) What are essential amino acids ?                                                                           2
            (b) Why is cellulose in our diet not nourishing ? ?
18.       State what are             :                                                                                                           2
            (i) anomers      (ii) mutarotation
19.       (a) What are conduction and valence bands ?                                                                       3
            (b) In the mineral spinel, having the formulaMgAl2O4 , oxide ions are arranged in the                          cubic closed packing , Mg++ ions occupy the tetrahedral voids and Al+++ ions                                   occupy the octahedral voids.
                 (i) What %age of tetrahedral voids is occupied by Mg++ ions ?
                 (ii) What %age of octahedral voids is occupied by Al+++ ions ?                                     
20.       Prove that the time required for completion of  ¾th  of a first order reaction is twice the time required for the completion of half of the reaction.                                         3
OR
A first order reaction takes 69.3 minutes for 50% completion. Set up an equation for determining the time required for 80% completion of this reaction.
21        What are :                                                                                                                    3
            (i) Inhibitors.
            (ii) Cataphoresis.
            (iii) Peptization.
22.       State why :                                                                                                                  3
            (a) Bleaching of flowers by Cl2 is permanent while that by SO2 is temporary.
            (b) Enthalpy of dissociation of F2 is much less than that for Cl2.
            (c) Nitric oxide becomes brown when released in air.
23.       Draw the structures  and write basicity of :                                                                3
            (i) Marshall’s acid  
(ii) Pyrophosphoric acid.
24.       (a) Give IUPAC name of Na3[Cr(OH)2F4].                                                                3
(b) Using valence bond theory predict the magnetic behaviour and geometry of
      [Cr(NH3)6]3+ ion. [ At no. Cr = 24 ]

25.       Write the products of the following reactions :                                                          3
           
(i)        

                                                               H    
                                                                           +      HBr        
           
                                    H                       H



            (ii)                                 CH2–– C ═ CH2    +    HBr      peroxide   
                                                               │‌‌
                                                               H



            (iii)                                OH     +    SOCl2      
                       




26.       (a) How does vulcanization changes the character of natural rubber ?                      3
(b) Comment on the structural difference between thermoplastics and thermosetting  
      polymers.
27.       (a) What type of drug phenacetin is ?                                                                         3
            (b) Give one important use of each of the following :
                  (i) Bithional.
                  (ii) Butylated hdroxy anisole.
28.       (a) What is lanthanide contraction ? Explain.                                                             5
            (b) Account for the following :
                  (i) Of the ions Co2+, Sc3+ and Cr3+ which one would give coloured aqueous solutions                          and why ?
                  (ii) Explain why chromium is a typical hard metal while mercury is a liquid.
                  (iii) Why in permanganate ion, there is a covalency between manganese and oxygen ?
OR
            (a) Complete the following :                                                                                      
                 (i) Cr2O72-  +  14H+  +   6e-            …………..   +   7H2O
               
    (ii) CrO42-  +   ………….                    …………….              …………..   + 4OH-
           
(b) Account for the following :
(i) Size of trivalent cations in the lanthanoid series decreases with increasing atomic
     number.
(ii) Transition metal fluorides are ionic whereas chlorides and bromides are usually
      covalent..
                 (iii) Chemistry of lanthanoids is quite similar..
29.       (a) Write down the reactions involved in the working of a H2––O2 fuel cell.
(b) A solution of Ni(NO3)2 is electrolysed between platinum electrodes using a current of  
     5.0 amperes for 20.0 minutes. What mass of Ni is deposited at the cathode.
                [ At. Wt. Ni = 58.7 ]                                                                                                5        
OR
            (a) (i) State Kohlrausch’s law.
                 (ii) Why does an alkaline medium inhibit the rusting of iron ?     
            (b) Calculate the equilibrium constant for the following reaction :
                       
Zn(s)  +  Cu2+(aq)                   Zn2+(aq)   +   Cu(s)

[ E0Zn2+/Zn   =  – 0.763 V and   E0ZCu2+/Cu  =  + 0.34 V ]   
30.       Write  chemical equations(only) for the following reactions :                                    5
            (a) (i) Etard reaction   
     (ii) Cannizzaro's reaction   
     (iii) Aldol condensation
            (b) Of aldehydes and ketones which would reduce Tollen's reagent ? Why
OR
(a) How will you prepare the following compounds from benzene ? you may use any
     inorganic reagent and any organic reagent having not more than one carbon atom.
     (i) p-nitrobenzaldehyde
     (ii) Methyl benzoate
     (iii) Phenylacetic acid
(b) Explain why carboxylic acids do not give reactions of aldehydes and ketones.


Paper Sumitted By:

Name                    Paramjeet Singh Hora
Email                   amol.preet@yahoo.com
Phone No.  009779804071549


Sample Paper – 2011
Class – XII
 Subject -
Chemistry

SET-II

Time : 3 Hrs.                                                                                                  MM : 70

            General Instructions :
            1.         All questions are compulsory.
            2.         Questions no. 1 to 8 are very short answer questions and carry 1 mark each.
            3.         Questions no. 9 to 18 are short answer questions and carry 2 marks each.
            4.         Questions no. 19 to 27 are also short answer questions and carry 3 marks each.
            5.         Questions no. 28 to 30 are long answer questions and carry 5 marks each.
            6.         Use log tables if necessary, use of calculators is not allowed.

1.         Give one example each of a triclinic and rhombohedral crystal type.                        1
2.         Write down the van’t Hoff equation w.r.t. solutions. Which colligative property can be calculated using the equation ?                                                                                1        
3.         Intrinsic colloids are reversible also. Comment.                                                         1
4.         State what are depressants in metallurgy ?                                                                 1
5.         Write down the structure of 2-(2-Chlorophenyl)-1-iodooctane.                                1  
6.         Write the structure of 1,4-Dibromobut-2-ene.                                                            1
7.         State what are enantiomers.                                                                                        1
8.         Why +5 state of Bi is less stable than +5 state of Sb ?                                               1
9.         (i) The reaction 2H2(g)  +  O2(g) →  2H2O is thermodynamically feasible. How is it that a  
                 mixture of H2 and O2 kept at room temperature has no tendency to form water ?
            (ii) Identify the reaction order if the unit of the rate constant is sec-1.                       2
10.       State what are :                                                                                                           2
            (i) Henry’s law ?
            (ii) relative lowering of vapour pressure ?
11.       Calculate the freezing point of a one molar aqueous solution of KCl.
            [ Density of the solution = 1.04 g/cc. , Kf = 1.86 K Kg mol-1 , At wt. of K = 39 and
Cl = 35.5]                                                                                                                    2
12.       State :                                                                                                                          2
            (a) One limitation of Ellingham diagram.
            (b) A chemical equation illustrating van-Arkel method.        
13.       Write balanced equations (only) for :                                                                         2
            (i) Reaction of ethanol with hot reduced copper.
            (ii) Reaction of  phenol with Br2 in the presence of CCl4 or CS2.
14.       p-Toluidine is stronger base than aniline. Why ?                                                        2
15.       Write equations  only corresponding to the following reactions :                              2
            (a) Carbylamine reaction
            (b) Diazotisation.


16.       How would you account for the following :                                                              2
            (i) Phenols are stronger acids than alcohols.
            (ii) Ethers are much lower boiling than the alcohols of comparable molar masses.
OR
Explain how an –OH group attached to a carbon atom in the benzene ring activates it towards electrophilic substitution.                                                                           

17.       (a) What is denaturation of proteins ?                                                                                    2
            (b) Why is cellulose in our diet not nourishing ? ?
18.       State what are             :                                                                                                           2
            (i)Zwitterion    (ii) reducing sugars
19.       (a) What are ferrimagnetic substances ?                                                                    3
            (b) In the mineral spinel, having the formulaMgAl2O4 , oxide ions are arranged in the                          cubic closed packing , Mg++ ions occupy the tetrahedral voids and Al+++ ions                                   occupy the octahedral voids.
                 (i) What %age of tetrahedral voids is occupied by Mg++ ions ?
                 (ii) What %age of octahedral voids is occupied by Al+++ ions ?                                     
20        What are :                                                                                                                    3
            (i) Zeta potential.
            (ii) Gold number.
            (iii) Peptization.
21.       State why :                                                                                                                  3
            (a) Bleaching of flowers by Cl2 is permanent while that by SO2 is temporary.
            (b) Enthalpy of dissociation of F2 is much less than that for Cl2.
            (c) Nitric oxide becomes brown when released in air.
22.       Prove that the time required for completion of  ¾th  of a first order reaction is twice the time required for the completion of half of the reaction.                                         3
OR
A first order reaction takes 69.3 minutes for 50% completion. Set up an equation for determining the time required for 80% completion of this reaction.
23.       Draw the structures  and write basicity of :                                                                3
            (i) Marshall’s acid  
(ii) Pyrophosphoric acid.
24.       (a) Give IUPAC name of [Co(NH3)5ONO]2+.                                                            3
(b) Using valence bond theory predict the magnetic behaviour and geometry of
      [Cr(NH3)6]3+ ion. [ At no. Cr = 24 ]
25.       (a) What are copolymers ? Give an example                                                               3
(b) Comment on the structural difference between thermoplastics and thermosetting  
      polymers.
26.       (a) Distinguish between antiseptics and disinfectants.                                               3
            (b) Give one important use of each of the following :
                  (i) Bithional.
                  (ii) Butylated hdroxy anisole.



27.       Write the products of the following reactions :                                                          3
           
(i)        
 

                                                               H    
                                                                           +      HBr        
          
                                    H                       H



            (ii)                                 CH2–– C ═ CH2    +    HBr      peroxide   
                                                               │‌‌
                                                               H



            (iii)                                OH     +    SOCl2      
                       





28.       (a) State two consequences of lanthanide contraction.                                              5
            (b) Account for the following :
                 (i) Vanadium pentoxide acts as a catalyst ?
                 (ii) In any transition series with increase in atomic number, the atomic radius does not                          change very much.
                 (iii) f-Block elements are called inner-transition elements.
OR
            (a) Complete the following :                                                                                      
                 (i) Cr2O72-  +  14H+  +   6e-            …………..   +   7H2O
               
    (ii) CrO42-  +   ………….                    …………….              …………..   + 4OH-
           
(b) Account for the following :
(i) Size of trivalent cations in the lanthanoid series decreases with increasing atomic
     number.
(ii) Transition metal fluorides are ionic whereas chlorides and bromides are usually
      covalent..
                 (iii) Chemistry of lanthanoids is quite similar..
29.       Write  chemical equations(only) for the following reactions :                                    5
            (a) (i) Etard reaction   
     (ii) Cannizzaro's reaction   
     (iii) Aldol condensation
            (b) Of aldehydes and ketones which would reduce Tollen's reagent ? Why
OR
(a) How will you prepare the following compounds from benzene ? you may use any
     inorganic reagent and any organic reagent having not more than one carbon atom.
     (i) p-nitrobenzaldehyde
     (ii) Methyl benzoate
     (iii) Phenylacetic acid
(b) Explain why carboxylic acids do not give reactions of aldehydes and ketones.
30.       (a) Write down the reactions involved in the working of a H2––O2 fuel cell.
(b) A solution of Ni(NO3)2 is electrolysed between platinum electrodes using a current of  
     5.0 amperes for 20.0 minutes. What mass of Ni is deposited at the cathode.
                [ At. Wt. Ni = 58.7 ]                                                                                                5        
OR
            (a) (i) State Kohlrausch’s law.
                 (ii) Why does an alkaline medium inhibit the rusting of iron ?     
            (b) Calculate the equilibrium constant for the following reaction :
                       
Zn(s)  +  Cu2+(aq)                   Zn2+(aq)   +   Cu(s)

[ E0Zn2+/Zn   =  – 0.763 V and   E0ZCu2+/Cu  =  + 0.34 V ]   



Paper Sumitted By:

Name         Paramjeet Singh Hora
Email         amol.preet@yahoo.com
Phone No. 009779804071549


SAMPLE PAPER -2011
CLASS – XII
Subject – CHEMISTRY


Time Allowed: 3 hrs                                                                                 Maximum Marks : 70
General instructions:
             1.  All questions are compulsory.
             2.                   Question No: 1-8 are very short answer questions and carry 1 mark each.
             3.                   Question No: 9-18 are short answer questions and carry 2 marks each.               
             4.                   Question No: 19-27 are also  short answer questions and carry 3 marks each.
             5.                   Question No: 28-30 are long answer questions and carry 5 marks each.
             6.                   Use log tables if necessary, use of calculators is not allowed.

1.       Can you store copper sulphate solution in a zinc pot?
2.       For a chemical reaction A→B , the rate increases by a factor of 1.59 when conc of A is doubled. What     is the order of this reaction ?
3.       What are micelles?
4.       Out of C and CO which is better reducing agent at 673 K and why ?
5.       What is the covalence of nitrogen in N2O5?
6.       Give one example each of cationic and anionic complex.
7.       Name the macromolecules that are chosen as drug targets.
8.       Define genetic code.
9.       With the help of a graph explain why it is not easy to determine λ0m for a weak electrolyte by          extraploting the concentration versus molar conductance curve as for        strong electrolytes.
10.     The rate constant of a first oredr reaction becomes 6 times when the temperature is increased from
          350 K to 410 K. Calculate the energy of activation for the reaction. (Gas constant R = 8.314 JK-1mol-1 )
11.     For a first order reaction , calculate the ratio between the time taken to complete three foutrh of the            reaction and the time taken to complete half of reaction.
                                                OR
               Consider the reaction:
            2 NO + 2H2 → N2 + 2 H2O.
          Write the most probable rate equation from the following data. What is the order of the      reaction?          Explain this method.
Experiment
       [NO]
          [H2]
Rate of reaction ( mol L-1 s-1 )
            
            I
          II
          III
          IV


      0.20
      0.40
      0.20
      0.60

         0.20
         0.20
         0.40
         0.20

    3.0 x 10-3
    1.2 x 10-2
    6.0 x 10-3
    2.7 x 10-2

12      a)Why does R3P=O  exists but R3N = O does not. ( R- alkyl group)
           b) PCl5 is ionic in the solid state. Why?
13.     What was the reasoning appiled by Neil Bartlett to prepare the first noble gas compound by carrying         out reaction of  Xenon and PtF6 ?
14.     [Fe(H2O)6]3+ is strongly paramagnetic whereas [Fe(CN)6]3- is weakly paramagnetic.           Explain.
15.     Give reasons.
          a) Ethylamine is soluble in water, whereas aniline is not.
          b) Although amino group is o- and p- directing in aromatic electrophlic substitution                                               reactions, aniline on nitration gives a substantial amount of m-nitroaniline.
16.     How is the activation of  benzene ring by the amino group reduced by acetylating aniline during       nitration?
17.     Pure silicon is an insulator, silicon dopped with phosphorus is a semiconductor. Silicondopped with            gallium is also semiconductor. What is the difference between two dopped silicon semiconductors?
18.     A mettalic element has a cubic lattice. Each edge of the unit cell is 288 pm. The density of  the metal is        7.20 g cm-3. How many (i) unit cells and ( ii) atoms will there  be in   100 g of the metal?
19.     a) Calculate the potential of  hydrogen elctrode in contact with a solution  whose pH is 10.
          b) How much electricity is required in coulomb for the oxidation of 1 mol of H2O to O2 ?
            ( Given 1 F = 96500 C )
          c) Write the products obtained at cathode and anode on electrolysis of concentrated sulphuric acid using              platinum electrodes.
20.     a) How is colloidal sol. of sulphur is prepared?
          b) Define gold number. What does receprocal of gold number indicate?
          c) Give one test to distinguish whether the given emulsion is oil in wtaer type or water in                              oil type emulsion.
21.     a) Copper can be extracted by hydrometallurgy but not zinc. Explain.
          b) How does NaCN acts as a depressant in preventing ZnS from forming the froth?
          c) Outline the principle of the method used for refining of silicon.
22.     a) Explain why inspite of nearly same electronegativity , oxygen forms hydrogen bonding  while                             chlorine does not.
          b) Arrange the following in the decreasing order of property indicated.
          i) ClO4-, BrO4-, IO4- - oxidising power.
          ii) F2, Cl2, Br2, I2- bond energy
          c) Write balanced equation for the thermal decomposition of ammonium dichromate.
23.     Explain why
          a) Grignard reagents should be prepared under anhydrous conditions.
          b) Haloalkanes react with AgCN forms isocyanides as major product.
          c) The dipole moment of chlorobenzene is lower than that of cyclohexyl chloride.
23.     Account for following:
          a) Dehydration of alcohols to form alkenes is always carried out with conc.H2SO4 and                               not with conc.HNO3.
          b) Ditertiary butyl ether cannot be prepared by Williamson’s synthesis.
          c) Hydrzones of CH3CHO are not prepared in highly acidic medium
24.     a). Give the structural formulae of the following α- amino acids.
            i) Glycine             ii) Alanine.
          b) Name the three physical and chemical changes that can cause proteins to denature.
          c) What is a prosthetic group
25.     a)What does PMMA stands for ? How is it prepared?
          b) What is the difference between two notations: Nylon-6 and nylon-66?
          c) Is ( CH2-CH(C6H5)n a homopolymer or copolymer? Is it an addition polymer or                                              condensation polymer?
26.     a) Read the following statement:
               “ Ranitidine is an antacid” . With reference to which classification has this statement                                  been given?
          b) What is meant by the term ‘broad spectrum antibiotics’
          c) Why do we require artificial sweetening agents?
27.     a)How will you bring about the following conversions.
          i) Ethanol to ethyl fluoride.
          ii) 1-chloropropane to 1-butanol
          b) Name the reagents used in the following reaction.
            Dehydration of propan-2-ol to propene.

28.     a) State Henry’s law for solubility of a gas in a liquid. explain the significance of Henry’s law constant.         At the same temperature , hydrogen is more soluble in water than helium. Which of them will have       higher value of KH and why?
          b) Explain elevation in boiling point of a solution with the help of vapour pressure temperature         diagram.
                                                   OR
          a)  Why is a molar solution of solute in water is more concentrated than a molal solution?
          b) Explain depression in freezing point of a solution on the addition of a solute. Show that depression in                             freezing point is a colligative property.
29.     a) Explain giving reasons
            i) Transition elements and their compounds exhibit paramagnetic behaviour.
            ii) Transition elements and their compounds are found to be good catalysts.
            iii) Cobalt ( II ) is stable in aqueous solution but in the presence of complexing agents , it                                                 is easily oxidised.
            iv) Of the d4 species , Cr2+ is strongly reducing while Mn( III ) is strongly oxidising.
            v) The transition elements exhibit high enthalpy of atomization.
                                       OR
          a) What is lanthanoid contraction? What are the consequences?
          b) Compare the chemistry of actinoids with that of the lanthanoids in reference to
               i) Atomic and ionic size   ii) oxidation state
          c) Complete the reaction Cr2O72- + Sn2+ + H+
30.     a) Carboxylic acids do not give the characteristic reactions of carbonyl group. Why?
          b) Although p-hydroxy benzoic acid is less acidic than benzoic acid, ortho-hydroxy                                              benzoic acid is about 15 times more acidic than benzoic acid. Explain.
          C) Name the product when benzophenone is reduced with Zn(Hg) in presence of HCl.
                                                               OR
          Describe the following reactions with one example each.
          i) Aldol condensation.
          ii) Hell volhard Zelinsky reaction.
          iii) Kolbe’s electrolysis.
          iv) Claisen condensation.


PAPER SUBMITTED BY :
Mr. DIPU. S. PILLAI
PH: 00971559909870
E-MAIL: dipusukumar@gmail.com, info@maseducationuae.com

Sample Paper – 2011
Class – XII
Subject – Chemistry
Time: 3 hrs.                                                                                                                                                      .
General instructions:
All questions are compulsory.
Marks for each question are indicated against it.
Questions number 1to 8 are very short –answer questions, carrying 1 mark each. Answer these in one word or about one sentence each.
Questions number 9 to18 are short –answer questions, carrying 2 marks each. Answer these in about 30 words each.
Questions number19 to27 are short –answer questions, carrying 3 marks each. Answer these in about 40 words each.
Questions number28 to30 are long-answer questions of 5 marks each. Answer these in about 70 words each.
 7 Use log tables, if necessary. Use of calculators is not permitted


Questions:

Q1. Which is a better nucleophilic addition reaction HCHO or C6H5CHO?                    (1)
Q2 .Why chloroform is needed to keep in brown colour bottle in dark.                           (1)
Q3 .How will you distinguish between CH3COOH and 2-phenylethanal?                                    (1)
Q4 .Write IUPAC name of the following compound:    
CH3COCOCH=CH-CONH-CH3                                                                                            (1)

                                                                              
Q5 .When uncalled  egg is kept in common salt then what will happen                                        (1)
Q6. Sodium chloride or calcium chloride is used to clear snow from the roads. Why?                             (1)
Q7 .What are solvate isomerim?                                                                                                                        (1)
   Q8 .What are ambidentate nucleophile?                                                                                                            (1)
Q9 (a) Write the mechanism of dehydration of alcohol.                                                                                      (2)
(b) Write Clemenson reduction.                                                                                                                        (1)
Q10 (a)Predict the the type of nucleophilic addition reaction when iso propyl bromide react with
                 KOH (aq) i.in the presence of Acetone   ii.in the presence of  Methanol                                                             (2)

Q11  Give reasons:
(i)                  Acid catalyzed dehydration of t-butanol is faster than that of n-butanol.      `                                   (1)
ii.How you can distinguish between phenol and benzyl alcohol?                                         (1)                                                                        
Q12 How will you convert acetaldehyde into following compounds?
           (i) Lactic acid             (ii) but-2-enal                                                                                                    (2)
Q13   (a) Arrange the following in increasing order of their basic strength:                                              (1)
                Methylamine, dimethylamine, N,N-dimethylamine,aniline (in aq medium)
          (b) Distinguish between 1°,2°,3° amine and aniline.                                                                                  (1)
Q14 Answer the following:
(i)                  Although — NH2 group is an ortho and para directing group, nitration of aniline gives along with ortho and para, meta derivatives also.                                                                                              (1)
(ii)                Aniline does not undergo Friedel crafts reaction.                                                                      (1)
Q15 Calculate the freezing point depressoion for 0.07 m aqeous solution of sodium sulphate ,if it is completely ionized in solution . if the freezing point of solution is -0.320 °C?                            (2)
(Kf=for water is 1.86°C)                                                                          
Q16 .Show the octahedral spiliting of d subshell . How Δo is related with pairing energy .                                (2)
Q17 (a) Define the kohlrausch law.       (1)
        (b) Which will have greater molar conductivity? Solution containing 1 mol acetic acid  in 200 ml or 1 mol of acitic acid in 500 ml.                                                                                             (1)
Q18.Calculate the Λ° for acetic acid .
if   Λ°m of HCl,NaCl,CH3COONa are 426,126,91 SCm2mol-1                                                            (2)
Q19 An organic compound (A) C5H11 Br on treatment with alcoholic caustic potash gives a hydrocarbon (B) C7H10. (B) on treatment with ozone and subsequent hydrolysis gives C and D.C does not give tollen’s reagent test ,both C&D gives idoform test. What are (A) ,(B),C and D. Explain reactions.   (3)
Q20 .A.Write the chemical equations, when phenol react with Br2.  i. in the presence of CS2  ii. in the presence of aq NaOH
B.When phenol react with Chloroform and NaOH.                                                                   (3)
Q21 (a) An organic compound (A) having molecular formula C3H8O on treatment with Cu at 3000C gives (B).  (B) does not reduce Tollen’s reagent but  gives positive iodoform test. Write down the structures of A and B.(1)
(b)  How will you convert?
(i) ethyl iodide to propanoic acid  (ii) Propionic acid to acetic acid (2)

Q22(a) Assign a reason for each of the following statements:
(i)                  pKb of Alkyl amines are less  than aryl amines.
(ii)                In aqueous solutions secondary Et2NH2>Et3NH>EtNH2.    (2)
(b) Write one method used for the preparation of pure primary amines.  (1)
Q23 Chloro acetic acid is a monoprotic acid and has Ka = 1.36 × 10–3. Calculate b. p. of 0.01 M aqueous soln ? (Kb = 0.51 k kg/mol)                              (3)
Q24 Answer the following questions:  (3)                     
(a) What does the graph indicates?                                                  
(b) Give an example of such liquids, which results in the formation
 of such graphs.
©Give reason for such behaviour.  

Q25 (a)  FeSO4 solution mixed with NH4(SO4)2solution in 1 : 1 molar ratio gives the test of Fe2+ ion butCuSO4 solution mixed with aqueous ammonia in 1 : 4 molar ratio does not give the test of Cu2+ on. Explain why? (1)
(b) Explain crystal field theory on the basis of splitting in octahedral complexes.   (2)
Q26 Write IUPAC names of the following coordination compounds:
(i)                  K3[Cr(C2O4)2]    (ii) [Co(NH3)6]ClSO4     (iii) [Co(en)2(ONO)Cl]Cl         (3)
Q27 Predict the direction in which the reaction will proceed if a cell is made by connecting silver electrode with mercury electrode.
E° = 0.80 V     E° = 0.79 V

            [Ag+] = 10–1 mol/l [Hg2+] = 10–3 mol/l
Also write cell representation.      (3)
Q28 Explain why?
(i)                  Acetic acid is a stronger acid than ethyl alcohol.
(ii)                Trichloroacetic acid is a stronger acid than acetic acid.
(iii)               Formic acid shows reducing properties.
(iv)              Carboxylic acids with five or fewer carbon atoms are water soluble but, higher ones are insoluble.
(v)                Acetic acid can be halogenated in the presence of phosphorous and chlorine but formic acid cannot be halogenated in the same way.        (5)
     OR
An organic compound (A) having molecular formula C9H10O forms an orange red precipitate (B) with , 2,4-DNP reagent. Compound (A) gives a yellow precipitate (C) when heated in the presence of iodine and NaOH along with a colourless compound (D). (A) does not reduce Tollen’s reagent or Fehling’s solution nor does it decolourises bromine water. On drastic oxidation of (A) with chromic acid, a carboxylic acid (E) of molecular formula (C7H6O2) is formed. Deduce the structures of the organic compounds (A) to (E).     (5)
Q29 Given below is the sketch of a plant for carrying out a process.









(i)                 Name the process occurring in the above plant.
(ii)               To which container does the net flow of solvent takes place?
(iii)             Name one SPM which can be used in this plant.
(iv)              Give one practical use of this plant. 
(v)                What will happen if the applied pressure is removed?      (5)
                                                   OR
(a)    What are azeotropes? What are their types? Give example in each case?  (3)
(b)   What is van’t Hoff factor? When it is used?   (2)                                       
Q30 (a) What are primary and secondary cells? Discuss Variation of molar conductivity with dilution.        (4)
      (b) What is abnormal molecular mass? (1)
                                       OR
(a)    What kind of complex should be formed in dry cell by NH3.   (5)                                  
(b)   How the corrosion is an electrochemical process ? give the reaction.
(c)    During the silver plating on a metal plate having area 10 cm2 in an electrolytic cell 15 A current is passed for one hour.What will be the thickness of silver plating if density of silver metal is 10.8 g/cm3 .




Paper Submitted by;

Omjeesingh
Phone no.        9859828945
omjeesingh@gmail.com


Sample Paper – 2011
Class – XII
Subject –
  Chemistry
Q1.In what kind of defect density of crystal increases.     1
Q2.Define the maximum boiling point azeotrope.1
Q3.Write the product of electrolysis of AgNO3 by using silver electrode.1
Q4.Define the elementary reaction .1
Q5.Write the I.U.P.A.C. name
 1
Q6.Define the term Ionization isomerism in co-ordination compounds.          1
Q7. Why N2 is less reactive than P4?   1
Q8. Why  transition metals act as good catalyst?1
Q9.R of 1 molar common salt solution filled in a cylindrical container having length 10 cm and radius 4 cm  is 500 ohm find the conductivity of solution.  2
Q10. The reaction between A and B is first order with respect to A and zero order
with  respect to B. Fill in the blanks in the following table.                                2

Exp.
[A] / mol L -1
[B] / mol L -1
Initial Rate
Mol L-1 min-1
01
0.1
0.1
2.0 ´ 10-2
02
-
02
4.0 ´ 10-2
03
0.4
0.4
-
04
-
0.2
2.0 ´ 10-2

Q11.Write the difference between physisorption and chemisorptions.2
Q12.A reaction is first order w.r.t. A and second order with respect  to B. 1.Write the differential rate   equation .2.How is the rate of reaction affected if concentration of B is increases three time   . 2
Q13.Discuss the contact process of preparation of sulphuric acid . 2.
Q14.What is lanthanide contraction ?      2
Q.15.What are the properties of a d-block elements which make them a good catalyst?   2
Q.16.1.Sulphur in vapour state exhibit paramagnetic behavior. Explain.    2
2.N2 is least reactive at room temperature .explain.
Q.17.1.Why does PCl3 fume in moisture.?      3
2. write the isoelectronic neutral species of  ClO-1 .
3.Write the increasing order of bod dissociation enthalpy of F2,Cl2,Br2,I2.
Q.18.How do you account for reducing nature of H3PO2 on the basis of its structure?     3
Q19.Silver crystallizes in F.c.c. ,if edge length is 4.07 x10-8  cm and density is 10.5 g/cm3 calculate the Atomic mass of silver.                    3
Q20.Explain the following term .1.ferromagnetism 2. Tetrahedral void 3. Frankel defect . 3
Q21. Q10.Convert following.
i). Aniline to chlorobenzene.1
ii).ethanol to chloro ethane.1
iii).CH3CH=C(CH3)2  +  HBr ­­­     peroxide                        ? (complete the reaction)1
. Q22. a) Define Azeotrops  and write one example each of minimum and maximum  3
     boiling azeotrops.
b) What are condition for ideal solution.
Q23.The time required for 10% completion of a first order reaction at 298 K is equal to that required for its 25% completion at 308 K.If the value of A is 4x1010 /s .Calculate k at 318 K and Ea.   3
Q24.Discuss the following terms.1.slectivity 2.hydrophillic sol  3.peptization.  3
Q25.1.Draw the structure of SF4,BrF3.      1x 3
2.P4 + HNO3 (conc) ----à  ?
3.How is the sulphuric acid prepared ?
Q26.1.  Show the Tetrahedral splitting of d subshell . How is the Δ0 is related with pairing energy for weak and strong ligand.?                                                                                           2
   2. Explain [Co (NH3)6] +3 is an inner orbital complex where as                          2
[Ni (NH3)6] +2 is an outer orbital complex ?
Q27. Calculate emf of cell at 25 0c for the following cell                                          3+2
                   Mg (s)   Mg +2  (0.01 M)      Sn +2  (0.1 M)   Sn (s)
Given E° Mg+2 / Mg (s) = -2.34 V  ;  E° Sn +2 / Sn (s) = -0.136 V 
1 F = 96500 C mol -1. Calculate the maximum work that can be accomplished
by the operation of this cell  .Define molar conductivity for the solution of an electrolyte. Discuss their  variation with concentration ?
                                                      or
  1. State two advantage of  H2-O2 fuel cell over ordinary cell.
.Calculate the cell potetential E cell of following cell.
Cu+2/Cu=  0.34 V         Ag+1/Ag= +0.80 V  and ( [Cu+2] =0.01 mol/L, [Ag1+] = 0.001 mol/L )
            Q28. (a) Discuss the chemistry involved in Brown ring test for nitrate ion. Give equations also.                                                                                                                                                 2
(b) Complete the following equations:                                                                 3
        (i)   P4 + SOCl2  ---------------à
        (ii) 4 AgNO3 + 2H2O + H3PO4 -------------à
          
(iii)                 NaCl + MnO2 + H2SO4 ------------------à

OR

(a) Account For the Following:                                                                    3
                  (i) H3PO2 act as monobasic acid.
                  (ii) Interhalogen compounds are more reactive than halogens
                  (iii) Bond dissociation energy of F2 is smaller than Cl2.
(b) Discuss the quantitative method for estimating O3 gas.                           2
Q29. Account for the following:                                                                                                      5
a)            Transition elements have higher boiling points
b)            Zn, Cd and Hg are normally not regarded as transition elements
c)             Transition metals exhibit higher enthalpies of atomisation..
d)            Transition elements show variable oxidation states and colour
Zr resembles with Hafnium

OR

 (i) Account for the following                                                                                                       1 x 3+2
(a)    Sc, the first member of first transition series doesn’t exhibit variable oxidation state.Account for the following                                           
(b)      Transition metals have a strong tendency to form complexes.
(c)       Zirconium (atomic no 40) and hafnium (atomic no 72) exhibit similar properties.
(ii) How does acidified solution of potassium dichromate react with (a) H2C2O4 and (b) KI?                        

Subject –Chemistry

  Q1.A mixture of FeO and Fe3O4 , When heated in air to constant weight ,gains 5% in its weight.Find out the composition of mixture.
Q2. The Vapour density of a mixture containing NO2 and N2O4 is 38.3 at 27°C.Calculate the moles of NO2 in 100 g mixture.
Q3.Calculate the Molality, molarity  of  90% by volume solution of  sulphuric acid whose specific gravity is 1.98 gml-1 .
Q4.The composition of air is N2 -78%,O2 –21% ,Ar—0.9%,CO2---0.1 % ,find the Molecular weight.
Q5. Calculate the molarity and molality of water.(density=1g/ml).Discuss the law of reciprocal proportion by mass and mole fraction.
Q.6 Calculate molality of 1 litre solution of 93% H2SO4 by volume?
Q.7 A sample H2SO4(density 1.787 g/ ml) is labeled as 86% by weight.What is  molarity of acid.what volume of acid has to be used to make 1 litre of 0.2 M H2SO4   ?
Q.8 A sample of NaOH weighing 0.38 gm is dissolved in water and solution is made to 50 ml in a volumetric flusk. What is the molarity of the resulting solution?
Q.9 4 litr of water is added to 2 litr of 6M HCL .What is the molarity of final solution
Q.10 Calculate the number of moles left after removing 10 molecules from 200 mg of CO2.
Q11. Calculate the molarity and molality of pure water.
    Q12. A solution is 25% water, 25% ethanol and 50% acetic acid by mass.Calculate the mole fraction of each component.
Q.13 A sugar syrup of weight 214.2 gm contains 34.2 gm of sugar. Calculate
                           (i)molal concentration
                           (i)mole fraction of sugar in the syrup.
Q 14 What volume of concentrated aqueous sulphuric acid which is 98% H2SO4 by mass and has a density of 1.84 gm/ml is required to prepare 10.0 L of  0.200 M H2SO4 ?
Q.15 A sample of ammonium phosphate contains 6.36 mol of hydrogen atoms . Find the number of moles of oxygen ato in the sample.
Q.15  Calculate the volume of 1.00 mol/litre aqueous sodium hydroxide that is neutralized by 200 ml of 2.00 mol/litre HCl acid and the mass of NaCl produced.
Q.16  Calcium Carbonate reacts with aqueous HCl to give CaCl2 and CO2 ..What mass of CaCO3 is required to react completely with 25 ml of 0.75 M HCl ?
Q. 20  (a) A sample of NaOH weighing 0.40g is dissolved in water and the solution is made to 50.0ml in volumetric flask. What is the molarity of the resulting solution?
(b) How many grams of NaOH should be dissolved to make 100 ml of 0.15 M NaOH solution?(3)

                 


PAPER SUBMITTED BY:  

Name   omjeesingh
Email   OMJEESINGH@GMAIL.COM
Phone No.        9859828945


Sample Paper – 2011
Class – XII
Subject –
Chemistry
Time: 3 Hrs                                                                              Max Marks: 70
General Instructions:
i.             All questions are compulsory.
ii.            Questions 1 to 8 are very short answer type carrying 1 mark each. Answer them in one sentence each.
iii.          Questions 9 to 18 are short answer type carrying 2 marks each. Answer each of them in about 30 words.
iv.          Questions 19 to 27 are also short answer type carrying 3 marks each. Answer each of them in about 40 words.
v.             Questions 28, 29 & 30 are long answer type carrying 5 marks each. Answer each of them in about 70 words.
vi.         Calculators are not permitted. Use log tables if necessary.
1
The value of DfGo for formation of Cr2O3 is – 540 kJ mol-1  and that of Al2O3 is – 827 kJ mol- Is the reduction of Cr2O3 possible with Al?
1
2
When NaBr is heated with conc H2SO4 ,Br2 is produced but when NaCl is heated with Conc H2SO4, HCl is produced. Why?
1
3
Write IUPAC name of:         C6H5 NHCOCH3
1
4
What is oxidoreductase?
1
5
Write IUPAC name of the ionization isomer of:  [Cr (NH3)5 Br] SO4
1
6
Write example of water in oil type colloid.
1
7
What is common in hcp and ccp types of solids?
1
8
Complete:                                       
                                      CH2CO CH2COO CH3             NaBH4

1
9
“The extraction of Ag by leaching with NaCN involves both oxidation and reduction”. Explain?
2
10
(i) How many faraday of charge is required for conversion of C6H5NO2 into
C6H5NH2?
(ii) During electrolysis of NaOH, Cl2 and H2 while for molten NaCl only Na metal and Cl2 gas are obtained. Explain these observations with suitable equation.
2
11
Explain the following:
(i) Clemenson reduction              (ii) Diazotization
2
12
(i) Why are transition metal compounds coloured?
(ii) Although Sc is the first transition element, its compounds are colourless. Why?
2
13
Which oxide of sulphur is capable of acting as oxidizing as well as reducing agent? Why?
2
14
(i) Draw diagram to illustrate the depression of freezing point when non-volatile solute is dissolved in a volatile solvent.
(ii) Two liquids A and B boil at 135 C and 1850C respectively. Which of them has a higher vapour pressure at 800C?
2
15
(i) Write mechanism for the cleavage of unsymmetrical ether having a tertiary group with HI.
(ii) Why ethyl ter-butyl ether cannot be prepared starting with ethanol?
2
16
How do you distinguish?
(i) Phenol & p-Cresol         (ii) Propanol and ethanol
2
17
(i) What is spectrochemical series?
(ii) Why are certain monodentate ligands called ‘ambidentate’? Give example.
OR
Discuss nature of bonding and magnetic property of the complex [Fe (CN)6 ]3- according to V.B theory. At. Number of Fe = 26
2
18
Give Reasons:
(a) Amines are weaker acids than alcohols.
(b) Phenol does not undergo acid catalyzed dehydration.
2
19
(a) What are the classes of neurologically active drugs? Write one example for each.
(b) What is the use of sodium benzoate in food?
3
20
(i) Why calculations based on colligative properties of solutions sometimes  gives abnormal molecular mass values for solute? What is the nature of the abnormalities?

(ii)  2g of C6 H5 COOH dissolved in 25g of benzene shows a depression in freezing point equal to 1.62 K. Molal depression constant for benzene is 4.9K kg mol-1. What is the Percentage (%) of association of acid, if it forms a dimer in solution?
3
21
 (i) Calculate the emf of the cell in which the following reaction takes place.
                       Ni (s) + 2 Ag+ (0.002 M)                          Ni 2+ (0.160 M)  + 2 Ag (s)    
Given that E0Cell = 1.05V
(ii) What are the products obtained at anode and cathode when aqueous NaCl is is electrolyzed with Pt electrodes?
3
22
Answer the following:
(i) How do you classify carbohydrates on the basis of their hydrolysis?
(ii) What are nucleic acids? Mention their two important functions.
3
23
(i) Chromium crystallizes in bcc structure. Its atomic diameter is 245 pm, find density. Atomic masses of:  Cr = 52u , NA =6.022 x 1023mol-1
(ii) In the face centered cubic arrangement of A and B atoms where A atoms are at the corner of the unit cell and B atoms at the face centres. One of the A atom is missing from one corner in the unit cell. What is the simplest formula of the compound?
3
24
Account for the following:
(i) Chlorobenzene is less reactive towards Nucleophilic substitution.
(ii) Ethyl amine has lower boiling point than ethyl alcohol.
(iii) pKa of ethanoic acid is greater than that of chloroethanoic acid.
3
25
(i) Critical temperatures of N2, CO, CH4 are 126, 134, and 110 K respectively. Arrange them in increasing order of adsorption on the surface of activated charcoal?
 (ii) What happens when a freshly precipitated Fe(OH)3 is shaken with little dil.FeCl3 solution? Explain with possible reactions.
3
26
(a) What are chain growth and step growth polymerization? Give examples.
(b) Write preparation of: (i) Novolac    (ii) Teflon
3
27
 (i) Which metal in the 1st transition series exhibits +1 oxidation state most frequently and why?
 (ii) Write down the number of 3d electrons in each of the following ions:
   Ti2+, V2+, Cr3+, Mn2+, Fe2+, Co3+, Co2+, Ni2+ and Cu2+    
Indicate how the five d orbitals are to be occupied for these hydrated ions (Octahedral)

OR

(a) In a given series the difference in the ionization enthalpies between any two successive d block elements is very much less than that in case of s and p block elements. Give the explanation.
 (b) Transition elements exhibit highest oxidation states in oxides rather than in fluorides. Why?
(c) An yellow translucent solution is obtained on passing H2S gas through an acidified solution of KMnO4. Identify the solution and write the balanced chemical equation.
3
28
(a) Complete the following chemical equations and balance them.       
            (i) NH3(excess)  + Cl2 è

             (ii)  P4  +  NaOH +   H2O   è  

             (iii)  XeF4    +   SbF5  è
(b) Describe the contact process for the manufacture of sulphuric acid. Write the conditions required to maximize the yield of sulphuric acid. Write equations to illustrate following properties of sulphuric acid:
(i) Strong acidic character     (ii) Low volatility
(iii) Dehydrating nature        (iv) Oxidizing action.

OR

(a) Bleaching of flowers by Cl2 is permanent, by SO2 it is temporary. Explain? (b) When conc. sulphuric acid was added to an unknown salt present in a test tube, a brown gas (A) was evolved. This gas intensified when copper turnings were also added into this tube. On cooling, the gas ‘A’ changed into a colourless gas ‘B’.
(a) Identify the gases A and B.
(b) Write the equations for the reactions involved.
5
29
(i) A reaction is 1st order in A and second order in B
(a) Write differential rate equation.    
(b) How is the rate affected when concentration of B is tripled?
(c) How is the rate affected when concentration of both A & B is doubled?
(ii) The kinetics of the reaction: A + 2B =>  Products;
    obeys the rate equation Rate = k [A]1[B]1 for it, find:
 a) Order of the reaction    b) Apparent molecularity of reaction
 c) Order of reaction when B is in large excess.

OR

(a) The rate of reaction, 2NO  + Cl2                                      2NOCl ,
 is doubled when concentration of Cl2 is doubled and it becomes eight times when concentration of both  NO and Cl2 are doubled. Deduce the order of the reaction.
(b) The time required for 10% completion of a first order reaction at 298 K is equal to that required for its 25% completion at 308K. If the pre-exponential factor for the reaction is 3.56 x 109 sec-1, calculate its rate constant at 318K and also the energy of activation.
5
30
(a) How do you convert the following?
          (i) Aniline to  N-methyl aniline
          (ii) Benzaldehyde  to α –hydroxy phenyl ethanoic acid
          (iii) 2-bromopropane to 1-bromopropane
(b) Arrange the following in the increasing order of property indicated:
     (a) CHF2 COOH, CHCl2 COOH, CH3 COOH  ------------- Acid strength
     (b) CH3 NH2,  (CH3)2 NH,  (CH3)3 N,  NH3          ---- Basic strength in solution
OR
(i) An unknown aldehyde A, C7H6O on reaction with KOH gives B and C. A reacts with Zn-Hg and conc HCl to give D which changes to A by CrO2Cl2. B on heating with soda lime gives E. identify A to E and write all reactions.
(ii) Write equations for:                                                                               
(a) Cross aldol condensation between propanal and ethanal in the presence of dil NaOH
(b) Preparation of 2-methyl propan-2-ol from a Grignard reagent.
5
     
Paper Submitted by:
Name        LawrenceVarghese
Email         lawrencevarg@yahoo.com
Phone No.            0096638281898



Sample Paper – 2011
Class – XII
Subject -C
hemistry
Time Allowed: 3 hours                                                                                                    Mm:70
  INSTRUCTIONS:        1 Q- 1-8 CARRY 1 MARKS EACH
                                   2 Q- 9-18 CARRY 2 MARKS EACH
                                   3 Q 19-27 CARRY 3 MARKS EACH
                                   4 Q-28-30 CARRY 5 MARKS EACH
                                   5  Give answer according to marks in order to save time..

                                                   Section-A
1. WHAT IS THE NATURE OF CRYSTRAL DEFECT PRODUCED WHEN SODIUM CHLORIDE IS DOPED WITH  MAGNESIUM CHLORIDE?1
2. A REACTION IS 50% COMPLETE IN 2 HOURS AND 75% IN 4 HOURS WHAT IS ORDER OF THE REACTION?. 1
3. DRAW THE STRUCTURE OF SEMICARBAZONE OF CYCLOBUTANONE 1
4. WHAT HAPPEN WHEN FERROMAGNETIC SUBSTANCE IS SUBJECTED TO HIGH TEMPRATURE?.1
5. WHAT IS RATE CONSTANT AND HOW DOES ITS VALUES VARY WITH REACTANT CONCENTRATION (1/2 + 1/2)
6. WHY IS SULPHURIC ACID NOT USED DURING THE REACTION OF ALCOHOLS WITH KI? 1
7. IN THE RING TEST FOR IDENTIFICATION OF NITRATE ION ,WHAT IS FORMULA OF THE COMPOUND RESPONSIBLE FOR BROWN RING
    FORMED AT  THE INTERFACE OF 2 LIQUIDS?.1
8. WHAT DO YOU UNDERSTAND BY TERM GLYCOSIDIC LINKAGE?.1
                                                                                          SECTION-B
9. ALUMINIUM CRYSATLISES IN A CUBIC CLOSE PACKED STRUCTURE .ITS METALLIC RADIUS IS 125pm
   A. WHAT IS LENGHT OF SIDE OF THE UNIT CELL. 1
   B. HOW MANY UNIT CELLS ARE THERE IN 1 meter cube of aluminium. 1
10. corrosion is essentially an electrochemical phenomenon .with the help of digram expalin the reactions occuring during the corrosion of iron. 2
11A. can the substance act both as colloid and crstalloid. 1
   B. WHY HYDROPHILLIC SOLS ARE MORE THAN HYDROPHOBIC SOLS 1
12. A. COMMENT " COLLOID IS  NOT A SUBSTANCE BUT A STATE OF SUBSTANCE". 1
      B.  EXPLAIN WHY DELTAS ARE FORMED WHERE RIVER AND SEA WATER MEET. 1
13. A. WHY IS Bi(V) IS STRONGER OXIDISNG AGENT THAN Sb(V). 1
      B. DRAW STRUCTURE OF PEROXODISULPHURIC ACID 1
                                                    OR
      WRITE CHEMICAL EQUATIONS FOR THE FOLLOWING
  1. ORTHOPHOSPHORUS ACID IS HEATED.1
   2. PTF6 AND XENON ARE MIXED TOGETHER.1
14. UNLIKE PHENOLS, ALCOHOLS ARE EASILY PROTONATED. 2
15. WRITE A SHORT NOTE ON
  A.   COUPLING REACTION 1   B. HOFMANN'S BROMAIDE REACTION 1
16. ACCOUNT FOR THE FOLLOWING
 A. CHLORINE WATER HAS BOTH OXIDIZING AND BLEACHING PROPERTIES 1
 B. ON ADDITION OF OZONE GA TO KI AOLUTION,VOILET VAPOURS ARE OBTAINED. 1
17. HOW WILL YOU DISTINGUISH BETWEEN
   A. ETHYLAMINE AND ANILINE. 1
    B. METHYL AMINE AND DIMETHYLAMINE 1
18. GIVE THE MECHANISM OF PREPARATION OF ETHOXYETHANE FROM ETHANOL 2
SECTION -C
 19. A COPPER-SILVE CELL IS SET UP . THE COPPER ION CONCENTRATION IN IT IS 0.10 M. THE CONCENTARTION OF SILVER ION IS NOT KNOWN. THE CELL POTENTIAL MEASURED IS 0.422V DETERMINE THE CONCENTRATION OF SILVER ION IN THE CELL 3
 20. DURING A NUCLEAR EXPLOSION ,ONE OF THE PRODUCT IS 90SR WITH THE HALF LIFE OF 28.1 YEARS .IF 1UG  OF 90SR  WAS ABSORBED IN THE BONES OF NEWLY BONE BABY INSTEAD OF CALCIUM ,HOWM MUCH OF IT WILL REAMIN AFTER 10 YEARS AND 60 YEARS IF IT IS NOT LOST METABOLICALLY. 3(PLEASE REFER QUETION NO. 17 FROM NCERT FOR PROPER STATEMENT IN TERMS OF SYMBOLS).
21. A NAME THE METHOD USED FOR REFINING OF
  A. NICKEL 1/2
  B. ZIRCONIUM  1/2
  C THE EXTRACTION OF AU BY LEACHING WITH NACN INVOLVES BOTH OXIDATION AND REDUCTION .JUTIFY GIVING WEQUATIONS. 2
22.HOW CAN YOU PREPARE XEOF4 AND XEO3 FROM XEF6 . 2
 B. HOW ARE INTERHALOGEN COMPOUNDS PREPARED?. 1
23. A. THE HEXAAQUAMAGANESE (II) ION CONTAINS FIVE UNPAIRED ELECTRONS,WHILE THE HEXACYANOMANGANESE(II) IONS ONLY CONTAIN ONE UNPAIRED ELCTRON.EXPLAIN USING CRYSTAL FIELF THEORY. 2
   B. WHAT IS BASIS OF FORMATION OF THE SPECTROCHEMICAL SERIES. 1
24. A. WHICH WILL HAVE HIGHRE BIOLING POINT - 1-CHLOROPENTANE OR 2-CHLORO-2METHYLBUTNAE. 1
      B. GIVE REASON: p-nitrochlorobenzene UNDERGOES NUCLEOPHILIC  SUBSTITUTION FASTER  THAN CHLOROBENZENE. EXPLAIN GIVING RESONATING STRUCTTURE AS WELL. 2
25. A. HOW DO YOU EXPLAIN THE AMPHOTERIC NATIURE OF AMINO ACIDS. 2
      B. WRITE REACTION WHEN GLUCOSE IS TREATED WITH ACETIC ANHYDRIDE. 1
26. WHAT ARE BIODEGRADABLE POLYMER. GIVE AN EQUATION OF BIODEGRADABLE ALIPHATIC POLYESTER (1+1)
     B. WHAT IS THE ROLE OF BEZOYL PEROXIDE IN POLYMERISATION O ETHENE. (1/2)
     C. HOW DO YOU EXPLAIN FUNCTIONALITY OF A MONOMER. 1/2
27. CLASIFY DETERGENTS GIVING AN EAMPLE IN EACH CASE. 3
                        OR
A. LOW LEVEL OF NONADRENALINE IS THE CAUSE OF DEPRESSION.WHAT TYPE OF DRUGS ARE NEDDED TOCURE THIS PROBLEM?.NAME TWO DRUGS(1/2+1).
B.  WHAT IS TINCTURE OF IODINE (1/2)
C. DEFINE CHEMOTHERAPY 1
                                                                          
SECTION -D
28. "THE OSMOTIC PRESSURE OBSERVED WHEN BENZOIC ACID IS DISSOLVED IN BENZENE IS LESS THAN EXPECTED VALUE". COMMENT 2
      B. A DECIMOLAR SOLUTION OF POTASSIUM FERROCYANIDE IS 50% DISSOCIATED AT 300K .CALCULATE THE OSMOTIC PRESSURE OF THE SOLUTION. 3
                                                                         OR
 A. DERIVE AN EXPRESSION TO EXPRESS THE REALTIVE LOWERING OF VAPOUR PRESSURE FOR A SOLUTION IS EAQUAL TO THE MOLE FRACTION OF THE SOLUTE IN IT WHNE THE SOLVENT ALONE IS VOLATILE. 3
 B. THE ELEMENTS A AND B FORM PURELY COVALENT  COMPOUNDS HAVING MOLECULAR FORMULA AB2 AND AB4.WHEN DISSOLVED IN 20 G OF BENZENE,1 g  OF AB2 LOWERS THE FREEZING POINT BY 2.3 K WHEREAS I g OF AB4 LOWERS IT BY 1.3K. THE MOLAL DEPRESSION CONSTANT FOR BENZENE IS 5.1K KG/MOL CALCULATE  THE ATOMIC MASS OF A AND B. 2
29. A. DESCRIBE HOW POTASSIUM DICHROMATE IS MADE FROM CHROMITE ORE AND GIVE THE EQUATIONS FOR THE  CHEMICAL REACTION INVOLVED.2
  B. WRITE THE BALANCED IONIC EQUATIONS FOR REACTING IONS  TO REPRESENT THE ACTION ACIDIFIED POTASSIUM DICHROMATE ON:
      1. POTASSIUM IODIDE SOLUTION 1
      2. ACIDIFIED FERROUS SULPHATE SOLUTION.1
  C. GIVE REASON: THE ENTHALIPIES OF ATOMISATION OF TRANSITION ELEMENTS ARE HIGH .1
30.   AN ORGANIC COMPOUND WITH MOLECULAR FORMULA C9H10O(  C-9 ,H-10,O) FORMS2,4-DNP DERIVATIVE ,REDUCES TOLLENS REAGENT AND UNDERGOES CANNIZZARO REACTION. ON VIGOROUS OXIDATION IT GIVES 1,2-BENZENEDICARBOXYLIC ACID.IDENTIFY THE COMPOUND. 3
.B  HOW WILL YOU CONVERT 
  1. BENZOIC ACID TO M-NITROBENZOIC ACId 1
2.  ETHANOL TO ACETONE. 1
                                                                  
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:1 for solution please refer latest  ncert book of CHEMISTRY  class xii
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Paper Submitted by
Name sharanjeet singh
Email  girls.r.like.seasons@gmail.com
Phone No.    0181-4633006