CBSE Sample Paper Class XII, Chemistry 2006

CBSE SAMPLE PAPER

CHEMISTRY

Time : 3 hrs.                          Class: XII                              M.M. 70
General Instructions:-

 

I    All questions are compulsory.

II  Marks for each question are indicated against it.

III Question numbers 1 to 5 are very short- answer questions each of 1 mark. Answer    

     them in one word, phrase or about one sentence each.

IV Question number 6 to 12 are short answer questions of 2 marks each. Answer them in  

     about 30 words each.

V  Question number 13 to 24 are short answer questions of 3 marks each. Answer 

     them in about 40 words each.

VI Question numbers 25 and 27 are long answer questions of 5 marks each. Answer them

    in about 70 words.

VII Use log table, if necessary.

1.       Give an example of water in oil type emulsion.

  1. Name the stoichiometric defect where the density of the crystal changes.
  2. If NaCl is doped with 10-3 mol % of SrCl2. What is the concentration of cationic vacancies?
  3. Write the name of [Co(NH3)6] [Cr(CN)6].
  4. When do you observe positive deviation from ideal solutions?
  5. Compare the bond order of N2 and N2+.
  6. For a first order reaction, it takes 5 minutes for the initial concentration of 0.6 mol/L to become 0.4 mol/L. How long will it take for initial concentration to become 0.3 mol/L?

OR

A reaction: Reactant à Product  is represented by

 
   

 

 

Conc. of                [R0]

          [R]

                             Time (t)

(i)                The order of the reaction in this case.

(ii)              What does the slope of the graph represent?

  1. Two ions A+ and B have radii 88 and 200 pm respectively. In the closed packed crystal of compound AB, predict the coordination number of A+.
  2. Reaction between NO2 and F2 to give NO2F takes place by the following mechanism.

NO2 (g) + F2 (g)      Slow                 NO2F (g) + F (g)

NO2 (g) + F (g)       Fast                  NO2F (g)

Write the rate expression for the reaction.

10. What are zeolites? Give an example for it.

11. What happens to the entropy of a substance of going from C(s) à C(l)

12. How is Bakelite prepared (equation only)?

13. The kinetic energy of a subatomic particle is 5.86X10-25 J. Calculate the frequency of the particle wave. (h=6.63X10-34 Js)

14. Explain : (a) Kolbe’s reaction (b) Friedal Craft Acylation of Anisole

15. Electrolytic conductivity of 0.20 mol/L solution of KCl at 298 K is 2.48X10-2 W-1cm-1. Calculate its molar conductivity.

16. (a) What is the basic unit of orthosilicates?

(b) How are silicones prepared?

(c ) SnCl2 is solid whereas SnCl4 is liquid; why?

17. Which is more reactive and why?

(a)  Acetaldehyde or Acetone (towards HCN)

(b) CH3COCl or CH3COOC2H5 (towards hydrolysis).

18. For a reaction K= 1.98X10-4 at 400K. What is the value of DG° at this temperature (R= 8.314 J/K/mole)?

19. Complete :

(a)                 COOH

 
   

 

 

                    Br2

          FeBr2

 

(b)                  CH3COOR’ + R’’OH      H

(c )     CH3CHO + NH2NH2 à

Table of Contents

OR

(a)  Describe with the help of suitable example:

(i) Diazotisation  (ii) Reimer-Tiemann’s reactions.

(b) Give one chemical test to distinguish between CH3CH2NH2 and C6H5NH2.

20. How will you convert:

(a)  Benzene to m-Dinitrobenzene.

(b) Aniline to Benzonitrile

(c)  Ethylamine to ethanol

21. Define with example (a) acid dye (b) tranquilizer (c) analgesic.

22. Calculate the emf and DG° of cell reaction for the following cell at 25°C.

Mg(s)  Mg2+ (0.001M)     Cu2+ (0.0001M) Cu(s).

E° values: Mg2+/Mg = -2.37V, Cu2+/Cu=+0.34V and F=96500C.

23. Compare the hybridization of [Ni(CN)4]2- and [Ni(CO)4].

24. (a) What advantage the osmotic pressure method has over the elevation of boiling point method for determining molecular masses?

(c)  What is the molar concentration of solute particles in the human blood if the osmotic pressure is 7.2 atm at a body temperature of 37°C (R=0.0821 atm K-1 mol-1 ).

25. Answer the following:

(a)     Give a reaction where acidified KMnO4 solution acts as an oxidizing agent.

(b)    How is general configuration of lanthanoids different from that of actinoids?

(c)     Name the chief ore of copper and zinc. How will you extract zinc from its ore?

OR

(a)    Name the chief ore of iron. Write the reactions involved in its extraction.

(b)   Compare the chemistry of actinoids and lanthanoids with special reference to (i)Electronic configuration (ii) oxidation states.

26. Answer :

(a)  [SiF6] 2- exists but [CF6] 2-  does not.

(b) Draw the structure of orthophosphoric acid.

(c)  H2O is liquid while H2S is a gas at room temperature.

(d) Reaction of hydrolysis of XeF6.

(e)  Arrange hydrides of halogens in order to increasing stability, give reasons.

27. Answer the following:

(a)  Give one example of reducing sugar and non-reducing sugar each.

(b) Name the nitrogen containing bases found in DNA.

(c)  Basic difference between starch and cellulose.

(d) Name the disease caused due to deficiency of essential amino acid.

What are phospholipids?

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