CBSE Sample Paper Class XII, Chemistry 2006




TIME 3 HRS.                                                                                                            M.M. 70



1.         Question paper consists of 27 question,  question no. 1-5 carries 1 marks each and are very short type question

  1. 2.                  Question No. 6-12 short type question carries 2 marks each
  2. 3.                  Question No. 13-24 short type question carries 3 marks each
  3. 4.                  Question No. 25-27 very long type question carries 5 marks each.
  4. 5.                  Calculators not permissible. Use of log book is permitted


1.         What is the significance of y and y2   

2.          Define radius ratio.

3.          On what factors the product of electrolysis at electrodes depend.

4.         What is boltzman factors  and Arrhenius equation.

5.           What is the reason for first increase and then decrease in the adsorption incase of chemisorptions.

  1. A compound of vanadium has a magnetic moment of 1.73 B.M. work out the electronic configuration  of vanadium in the compound.       
  2.      The composition of a sample of wutstite in Fe0.93 O1. What percentage of the iron      is present in the form of Fe(III).

8.         Define the following (i) III rd law of thermodynamics &(ii)standard Entropy of formation.

9.         A zinc rod in dipped in 0.1 M solution of ZnSo4.The salt in 95% dissociated at this dilution at 298 k Calculate the electrode potential (E =-0.76V).

10    A conductivity cell has its electrodes 1cm a part and each electrode has area of cross section 2cm2 when filled with  N/50m ,The cell shows a resistance of 166.50         calculate the equivalent  conductance of mix at the given conctration

11     What is emulsion ? Write its application.

12  (1) Why  H3PO3 is deprotic /dibasic ? (2) PH3 is weaker  base  then NH3 why?

13.       Find out  hybridization and also oxidation  K[Co(co4)]

14.       (a)       n-propylamine has a higher boiling point than trimethylamine why ?

(b)               aniline hydrogen sulphate, on heating, forms a mixture of ortho 0.4 para amino sulphunic  acid ,

15    write the mechanism of preparation of neoprene ?

16    Explain the lock and key mechanism of enzyme action with digramatic representation17

17    Explain the structure and properties of phospholipids in brief

18    What is antioxidants?Give some examples with their structure

19    The degree of dissociation of Ca(NO3)2 in a  dilute aqueous solution contening  8.09 of  the salt per 100g of water at 100          is70% if the upper pressure of water 100    is 670 mm              calculate the vappour pressure of the the solution.

20    What will the initial rate of a reaction if its rate constants is10–3 min–1  and the concentration of the reactant is 0.2 mol dm–3 ? how much of the reactant will be converted into product in 200 minutes

21    Write the extraction steps of lead form carbon reduction process

22      How will you differentiate between nitrites and isonitriteCompare and contrast the physical properties of alkyl cyanides and isocyanides.

 What is lanthanide contractin ? How would you account for it ? what are its important   consequence? Write the common oxidation states of lanthanides and actinides .

State Roult’s law for solutions. Why do water and ethanol and chloroform and acetone solutions deviate from Roult’s law? State the nature of deviations in each case and give reasons for it.

Illustrate with an example what is meant by standard free energy change of formationofcompound State the relation between standard free energy change and equilibrium constant of a chemical reaction.

26.       Account for the fololowing observation:

[I]        Beryllium resembles aluminium in several properties.

[ii]        The oxidation state of lead is more stable +2 than +4

[iii]       Ammonia is more basic than phosphine

[iv]       Hydrogen fluoride has higher boiling point than hydrogen chloride

[v]        Nitrogen is fairly inert

27        Calculate the E.M.F. and d G of cell reaction for the following cell at 25 C


E’Mg(s)|Mg2+ =-2.37 V                    E’Cu2+|Cu(s) =.34 V

F= 96500 C/mol

How long will it take an electric current of 0.15 A to deposit all the coper from 500 ml of 0.150 M copper sulfate solution?

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