Download CBSE Guess Paper Informatics Practices Class XII (12th) 2008

GUESS PAPER – 2008

Class – XII

SUBJECT - Informatics Practices (SET-3)

Time: 3 hours                                                     Maximum Marks: 70 General Instructions

1. All questions are compulsory. 2. Question nos. 1 to 8 are very short answer questions and carry 1 mark each. 3. Question nos. 9 to 18 are short answer questions and carry 2 marks each. 4. Question nos. 19 to 27 are also short answer questions and carry 3 marks each. 5. Question nos. 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.    Mention one property which is caused due to presence of F –centre in a solid?

2.    The decomposition reaction of ammonia gas on platinum surface has a rate constant = 2.5 x 10-4 mol L-1 S-1.  What is the order of the reaction?

3.    Give the IUPAC name of the following compound:(CH3)2NHC2H5

4.    What is the effect of Schottky defect and Frenkel defects on the density of crystals.

5.    A reaction is first order in A and second order in B. How is the rate affected when the concentration of both A and B is doubled.

6.    Give the structure of : 4 - methyl pent -3- en - 2 – one

7.    In the ring test for identification of nitrate ion, what is the formula of the compound responsible for the brown ring formed at the interface of two liquids?

8.    Except for vitamin B12, all other vitamins of group B, should be supplied regularly in diet. Why?

9.    Niobium crystallizes in body –centered cubic structure .if density is 8.55 g/cm3 .calculate atomic radius of niobium using its atomic mass 93 u.

10.    How do you account for conductivity of strong and weak electrolyte with concentration? Plot the graphs also.

11.    Differentiate between the following: (a) Lyophobic & Lyophilic sol

12.    Explain the following observations:

(a) An electrolyte NaCl is added to hydrated ferric oxide

(b) Electric current is passed through a colloidal sol.

13.(a) Describe Brown ring Test.

(b) R3P=O exist but R3N=O does not. Why

OR

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