XII,CHEMISTRY CBSE PAER-2018-SET-A

                      SET-1 -2018              

                                           MODEL  SET  PAPER

  CLASS - XII CHEMISTRY MODEL PAPER – (043)—2018

  Time : Three hour                                                                 Max. Marks : 70

General Instructions :-

 1. All questions are compulsory.
 2. Question No. 1-5 are very short answer questions and carry 1 mark each.
 3. Question No. 6-10 is short answer questions and carries 2 marks each.
 4. Question No. 11-22 is also short answer questions and carries 3 marks each.
 5. Question No. 23 is value added questions and carry 4 marks.
 6. Question No. 24-26 carry 5 marks
 7. Use log tables if necessary, use of calculators is not allowed.

 Q1.Write composition of dettol.?                                                                                         1

 Q2. What is role of NaCN in froath flotation process.?                                                        1

Q 3. What is relation  between Zr and Hf.?                                                                          1

 Q4. Write IUPAC name of the following compound C₆H₅CH(OH)-CONH₂.                       1

 Q5.Why density decrease during schottky defect.?                                                            1

 Q6. 19.5 gm of CH₂FCOOH were dissolve in 500 gm of water Then it dippresed F.P by 1⁰C  If K_f is 1.86 K Kg/ mol. Then find out vant Hoff facor and dissociation constant?               2

Q7.   50% of a substance disintegrate in 10 minute follow the first order kinetics.How much  time it will take to complete 75%.                                                                                        2

Q8.Drow the structure of

            (i)H₃PO₄          (ii) XeOF₄.                                                                                        2

 Q9. Urea (molar mass = 60 g mol¯ 1) is present in a solution having osmotic pressure of   

4.12atm. Calculate the weight of urea present in it if the room temperature is 270⁰ c.If same weight of glucose has been taken in place of urea then find out osmotic

         pressure.                                                                                                                        2

OR

If  0.2M   K₄[Fe(CN)₆]  undergoes 40% dissociation.Find out its vant hoff factor and dissociation constant

Q10.Write all the chemical reactions for the preparation of H₂SO₄.?                                 2

 Q11.   Define

              (i) Hardy schulze rule.? .
              (ii)What do you mean by Electrophoresis.

             (iii)What is critical micells concentration                                                            3

Q12. Explain the following:-

            (i)What do you mean by Zwiter ion.?
            (ii)Give chemical equation when glucose react with red phosphorous and HI..
            (iii)Why humane beings are unabl to digest cellulose.?.                                            3

 Q13. Define the followings:-

           (i) What is Glycosidic linkage.give example.?

           (ii) What is PHBV.give their uses..

           (iii) What are Tranquilizres drugs.why we should not use them without the 

             supervision of doctor.                                                                                              3

 Q14. (i)What is Kohlrausch,s Law.                                                                                      1

           (ii)Conductivity of 0.00241M acetic acid is 7.896x10^-5 S Cm^-1.Calculate its molar

     conductivity and if standard molar conductivity is 390.5 Scm² mol^-1.What is its

     dissociation constant.?                                                                                                      2

Q15. Write short notes on the following name reaction :           

              (i) Clemensen reaction
              (ii)Rosenmund reaction
               (iii)Garbriel pthalamide reaction                                                                                3

 Q16. (a)Write chemical tests to distinguish between compounds in each of the following

            pairs:

                (i) Propyl alcohol and Ethyl alcohol
                (ii) Butane-2-ol and Butanaol

 (b)Why Direct nitration of Aniline is not safe ?                                                                    3

                                     

 Q17.Arrange the following compounds in

             (i)HCHO,CH₃CHO.CH₃COCH₃,CH₃COCH₂CH₃

                                                           (Nucleophilic addition reaction

             (ii) 2-chlorobenzoic acid.2-methy benzoic acid.benzoic acid

                                                           (Acidic increasing order)
             (iii) CH₃CH₂CHO,.CH₃COCH₃,CH₃CH₃COCH₂CH₃

                                                        (Reaction toward grignard reagent)                            3
                                                                         

 Q18.Explain with suitable reason

       (a)Aniline cant be prepared by Garbriel pthalamide reaction.Expalin.

       (b) Phenol show acidic character.?

       (c)Why t-Butyl chloride does not give Williamson synthesi with sodium ethoxide.?   3

Q19.Give reason

       (i)What role of semipermeable membrane play in plasmolysis..?
       (ii) K₂Cr₂O₇ have no electron in its d-orbital.yet it is coloured .why                                  3

                                                                 OR
         (i) A Nacl compound has density of 6.125 g cm-3. If the edge length of its cubic unit cell             is 400 pm,. Calculate the molecular mass of Nacl.?
         (ii) Define what is n-type and p- type semiconductor.give example.?.

 Q20. Write names of monomer/s of the following polymers and give important uses..

 (a) Bakelite
            (b) Nylon-6   

(c) Decron                                                                                                    3

Q21. (a) Give the IUPAC name of : K₃[Co(cl)₃ (NH)₃]

           (b)Drow the splitting diagrame for TETRHEDRAL complex and define what is                              CFSE.How its magnitude change with strngth with ligands.?.                                                                    3

 Q22. Explain the following observations:

      (a) What are antihisatmins.Give an example?
      (b) What is difference between antiseptics and disinfectant.
      (c)Write three difference between DNA and RNA..?                                                       3

 Q23. A student living on a hill station has surveyed the area and found most cases in

hospital are of stones in gall bladder or kidney. He analyzed the water and found presence of Ca2+ ions. He conducted titration of water sample with EDTA (quantitative analysis) to prove his survey.

Contextual Question:-

a) What is the full form of EDTA?                                                                                  (1/2)

b)What is reason that most of the hill station persons are suffered fron kidney stone                                                                                                                                                  (1/2)

c) Why is EDTA preferred over any other ligand?                                                            (1)

d) What values do you think were in mind of the student while conducting quantitative analysis?                                                                                                                          (2)

 Q 24. Explain with reason:-

 (a)Why are aldehydes are more reactive than ketones when undergo nucleophillic

      addition reaction?                                                                                                            2

(b)During preparation of esters from a carboxylic acid and an alcohol in the presence of

     acid catalyst water or ester formed should be removed as soon as it is formed.          2

(c)Why does methanal not give aldol condensation while ethanol gives?                         1

                                                             OR

  (a)An organic compound ‘A’ with molecular formula C₈ H₈ O₂ is reduced to 2- ethyl

phenol on treatment with LiAlH ₄. ‘A’ forms a oxime with hydroxylamine and gives positive lodoform test and not a Tollen’s test. Identify the compound A and deduce its structure.

 (b) Write the chemical equations for the following conversions:

                 (i)Ethyl chloride into propanoic acid

                (ii) Benzyl alcohol into Benzoic acid
                (iii) Acetone to tert-Butyle alcohol

 Q25. (a) H₂O is liquid but H₂S is gas.?                                                                                1

           (b) SF₆ is more stale then SF₄                                                                                       2
         (c) What are allotropic form .Which allotropic form of phosphorous is more  

             reactive .Explain .why?                                                                                              2

                                                              OR

 (a) Give reasons for the following :

             (i) Oxygen is gas but sulphur is solid.?                                                                      1
            (ii) Why IF₇ is more reactive then F₂.?                                                                        1

 (b) Complete thye following equation
            (i) Cr₂ O₇^-- + H ⁺ + C₂H₅OH    ------à                                                                         1
             (ii) XeF ₄ + O₂ F₂              ------à                                                                                1
            (iii) 2H3 PO3                           --------à                                                                        1

Q 26. Give reasons for the following:

         (a) ClF₃ is known but Fcl₃ does not known. ?
         (b) Carbon show more catenation then phosphorous.?
         (c) ICl is more reactive than I₂ ?

          (d)Drow the structure of N₂0₅.
           (e)Only Xe from inert gases make compound with O and F atom. While other gases does not.                                                                                                                              5
                                                                            OR
   (a) Complete the following reaction:-
              (i)2Mn^{4 –} + 10 I ^– + 16 H– --------→

             (ii)2Mn^{4 –} + H₂O + I^– --------- →

  (b )Write complete chemical equations for
           (i)Preperation of KMnO₄ from pyrollusite .                                                             (3/2)
           (ii) Preperation of K₂Cr₂O₇ from chromite.                                                             (3/2)

*********************************************************DR SUDHIR TOMAR

                                                  (M.Sc(inorganic chemistry),M.SC(physical chemistry)

                                                   M.Ed,ph.D

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