XII-CHEMISTRY CBSE 2015 MODEL PAPER SET - 1

                  SAMPLE QUESTION PAPER

                           CHEMISTRY (043)

                        CLASS- XII - (2014-15)

: Time Allowed: 3 Hrs                                                          Maximum 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.

1. Why a Schottky defect is formed when calcium chloride is added to silver chloride crystal?

2. Give the IUPAC name of .

       CH₃-CH(OH)-CH(Cl)-COOH

3.Which compound give faster electrophilic substitution reaction  between Benzene and toluene.explain.?

4. Draw the structure of N-N, dimethyle butanamine

5. Why the process of adsorption is always exothermic?

6. Define (i) colligative properties (ii) vant hoff factors (iii) henery Law

OR

5% Aqueous solution of glucose is isotonic with 0.897% solution of urea . find out molecular mass of urea.?

7. what do you mean by activation energy. How a catalyst increase the rate of reaction.?.

8. Write the chemical reaction for the preparation of KMnO ₄.

9. (i)Aniline can’t be prepared by Gabriel pthalamide reaction.?

     (ii) Phenol show acidic character .How?

10. Write the following name reaction

(i) Halloform reaction

(ii)Clemmenson reaction

11. Write a note on the following with an example each:

(i). Hardy scheulze rule

(ii). Dialysis

(iii) Shape selective catalysis.

12. Write a note on:

(i )Write roll of iodine in the isolation of Zirconium.

(ii). What is roll of NaCN in the froath fotation process

(iii)Write the name of process used for extraction of Ni.

13. Answer the following:

i.Ni_0.98 O_1.OO is a compound in which Ni is present with +2 and +3 oxidation state. Find

   out percentage of both form of nickel.

ii. Why density decrease during Schottky defect.

OR

(i)            Atom X present at the corner of unit cell while atom y is at the center of each face. Find out empirical formula of the unit cell.

(ii)            

(iii)          What do you mean by F-center.?

14. 19.5 gm of CH ₂FCOOH is dissolve din 500 gm of water and then F.P depressed by 1 ⁰

            C.Using Kf = 1.86 find out its Vant Hoff factor.

15  If 90% of a reaction complete in 5 min .Find its half life period.

16. Give reasons:

(i)            Give example of hexadentate Legends (ii) What id hydrate isomerism give example.

(ii). Write IUPAC name of the following compound

          K ₄ [Fe (CN) ₆(NH₃.)]

17 (i) Why Cr ²⁺ is reducing and Mn ³⁺ is oxidizing where both has d ⁴ configuration.

      (ii)What is Lanthanides contraction? Explain reason?

     (iii)Why Mn ²⁺ is stable then Mn ³⁺?

18. (i) Iproniazole is used as a tranquillizers.

      (ii) Write composition of Dettol.

     

     (iii)What is harmfull effect of pain killer in excess.

19.   Write the formula of main product formed in the following chemical reactions.

 (i) CH₃Br + AgF

              (ii) CH₃CH₂Br + Nal  

            (iii) Arange the Acidity order of oxo acid of chlorine is

           HOCl , HOClO , HOClO₂ , HOClO₃

                                                               

20. Give reasons

i. HI is better reagent than HBr for cleavage of ether.

ii. Highly branched carboxylic acids are less acidic than unbranched acids.

(iii)Aniline does not give friedal craft reaction.?

21.    Differentiate the following pair of polymers based on the property mentioned against each.

(i) Novolac and Bakelite (structure)

(ii) Buna-s and Terylene (intermolecular forces of attraction)    

(iii)Write monomer structure of nylon -6,6.

22. Give the reason for the following:

a. Drow the structure of H3 PO₄   AND   H₂ S₂ O₈

b. Why Pcl ₅ is ionic in solid state.

23.      Sara went to market to buy fruits and vegetables. The vendor put the fruits and    

 Vegetables     in the polythene bag but Sara ask the vendor to put the things in the jute

Bag which he Carried with him. Now answer the following question

a.    Why did Sara refuse to use polythene bags?

b.    As a student of chemistry why would you advocate the use of jute bags instead of

polythene bags? Which values are promoted through the use of jute bag?

c. Suggest two activities to promote these activities

24. Convert the following:

          a. Toluene to benzaldehyde

          b. Ethanal to but-2-enal.

            ( c)  The following chemical reaction is occurring in an electrochemical cell.

                 Mg(s) + 2 Ag⁺ (0.0001 M) Mg²⁺ (0.10M) + 2 Ag(s)

               The electrode values are

Mg²⁺ / Mg = – 2. 36 V

Ag⁺ / Ag = 0.81 V

For this cell calculate EMF of the cell.

         

OR

(i)            Write a suitable reaction for the preparation of t-butylethyl ether from alky halide and sodium alkoxide.

(ii)           Write mechanism of dehydration of ethyl alcohol in presence of strong acid. And what happen if this reaction is carried out at Law temperature?

(iii)              What is the order of the reactions?

(iv)      What are the units of rate constant k for Zero order?

   (v) Give the relationship between k and t ½ (half life period) for Zero order reaction

25. . A mixed oxide of iron and chromium FeOCr₂O₃ is fused with sodium

            Carbonate in the presence of air to form a yellow coloured compound (A).

            On acidification the compound (A) forms an orange coloured compound (B),

            Which is a strong oxidizing agent? Identify

(i) The compounds (A) and (B)

(ii) Write balanced chemical equation for each step   

                                                                                                OR                

Heptanes and octane form an ideal solution at 373 K, The vapour pressures of the pure liquids at this temperature are 105.2 KPa and 46.8 KPa respectively. If the solution contains 25g of heptanes and 28.5g of octane, calculate

(i) Vapour pressure exerted by heptane

(ii) Vapour pressure exerted by solution

(iii) Mole fraction of octane in the vapour phase.                         

26. Account for the following facts

(a) State kohalraush Law..

(b) Write chemical; reaction for the lead storage battery during discharge.?

(c) Limitation of Henery law. 

(d)Faraday second law of electrolysis.

(e)Define Molar conductivity.                                 

                                    OR

            a) Can lanthanum ion exist in +4 oxidation state? Justify.

b) Why europium (II) more stable than cerium (II).

c) write advantage of fuel cell.

             d) define electrode potential

e)State  Faraday first law of electrolysis