Select Board & Class

Login

Board Paper of Class 12-Science 2007 Chemistry (SET 1) - Solutions

General Instructions:
(i) All questions are compulsory.
(ii)  This question paper consists of four sections A, B, C and D. 
Section A contains 5 questions of one mark each.
Section B is of 7 questions of two marks each.
Section C is of 12 questions of three marks each and
Section D is of 3 questions of five marks each.
(iii) There is no overall choice. However, an internal choice has been provided.
(iv) Wherever necessary, the diagrams drawn should be neat and properly labelled.
  • Question 1

    Find out the number of atoms per unit cell in a face-centred cubic structure having only single atoms at its lattice points.

    VIEW SOLUTION
  • Question 2

    State the condition resulting in reverse osmosis.

    VIEW SOLUTION
  • Question 3

    Express the rate of the following reaction in terms of disappearance of hydrogen in the reaction.

    VIEW SOLUTION
  • Question 4

    Name the following compound according to IUPAC system:

    VIEW SOLUTION
  • Question 6

    (a) Write the mathematical expression for the relationship of the wavelength (λ) of a moving particle and its momentum (P)

    (b) What physical meaning is attributed to the square of the absolute value of wave function, ?

    OR

    State the Heisenberg Uncertainty Principle and explain as to why it is not of real consequence when applied to a macroscopic object, like a cricket ball.

    VIEW SOLUTION
  • Question 7

    Define Conductivity and molar conductivity for the solution of an electrolyte.

    VIEW SOLUTION
  • Question 8

    How would you account for the following?

    (i) Sulphur hexafluoride is less reactive than sulphur tetrafluoride.

    (ii) Of the noble gases only xenon forms known chemical compounds.

    VIEW SOLUTION
  • Question 9

    On the basis of the standard electrode potential values stated for acid solution, predict whether Ti4+ species may be used to oxidise FeII to FeIII

    VIEW SOLUTION
  • Question 10

    What are chiral objects? Indicate the presence of centre of chirality, if any, in the molecules of 3-bromopent-1-ene.

    VIEW SOLUTION
  • Question 11

    How may the following conversions be carried out?

    (i) Propene to propan-2-ol

    (ii) Anisole to phenol

    (Write the reaction only).

    VIEW SOLUTION
  • Question 12

    Write formulae of the monomers of polythene and Teflon.

    VIEW SOLUTION
  • Question 13

    Define bond order in a diatomic molecule. Find the bond order in O2molecule. State and explain magnetic character of molecular oxygen.

    VIEW SOLUTION
  • Question 14

    Assign reasons for the following:

    (i) Phosphorus-doped silicon is a semiconductor.

    (ii) Schottky defect lowers the density of a solid.

    (iii) Some of the very old glass objects appear slightly milky instead of being transparent.

    VIEW SOLUTION
  • Question 15

    A 0.1539 molal aqueous solution of cane sugar (mol. mass = 342 g mol−1) has a freezing point of 271 K while the freezing point of pure water is 273.15 K. What will be the freezing point of an aqueous solution containing 5 g of glucose (mol. mass = 180 g mol−1) per 100 g of solution?

    VIEW SOLUTION
  • Question 16

    Calculate the standard cell potential of the galvanic cell in which the following reaction takes place:

    Also calculate the ΔrG Θ value of the reaction.

    (Given and F = 96500 C mol−1)

    VIEW SOLUTION
  • Question 17

    The rate constant for a first-order reaction is 60 s−1. How much time will it take to reduce the concentration of the reactant to 1/10th of its initial value?

    VIEW SOLUTION
  • Question 18

    Describe the following types of colloids, giving an example for each:

    (i) Multimolecular colloids

    (ii) Macromolecular colloids

    OR

    Explain the following terms with a suitable example in each case:

    (i) Shape-selective catalysis

    (ii) Dialysis

    VIEW SOLUTION
  • Question 19

    How would you account for the following?

    (i) The transition elements have high enthalpies of atomisation.

    (ii) The transition metals and their compounds are found to be good catalysts in many processes.

    VIEW SOLUTION
  • Question 20

    Describe for any two of the following complex ions, the type of hybridisation, shape and magnetic property:

    (i)

    (ii)

    (iii)

    VIEW SOLUTION
  • Question 21

    Complete the following statements for nuclear reactions:

    (i)

    (ii)

    (iii)

    (Note: You may use ‘X’ as symbol if the correct symbol in a reaction is not known)

    VIEW SOLUTION
  • Question 22

    Write one chemical equation for each, to illustrate the following reactions:

    (i) Rosenmund reduction

    (ii) Cannizzaro reaction

    (iii) Fischer esterification

    VIEW SOLUTION
  • Question 23

    Account for any two of the following

    (a) Amines are basic substances while amides are neutral.

    (b) Nitro compounds have higher boiling points than the hydrocarbons having almost the same molecular mass.

    (c) Aromatic amines are weaker bases than aliphatic amines.

    VIEW SOLUTION
  • Question 24

    (a) Describe and illustrate with an example each, a mordant dye and a detergent,

    (b) Give an example of a liquid propellant.

    VIEW SOLUTION
  • Question 25

    (a) Prove that ΔGsystem= − TΔStotalfor a system which is not isolated.

    (b) The decomposition of Fe2O3is a non-spontaneous process

    Show that the reduction of Fe2O3by CO can be made spontaneous by coupling with the following reaction:

    OR

    (a) Define the following terms:

    (i) Entropy

    (ii) A spontaneous process

    (b) Given below are the standard Gibbs energy changes for two reactions at 1773 K:

    Discuss the possibility of reducing Al2O3with carbon at this temperature. Given that:

    VIEW SOLUTION
  • Question 26

    (a) Assign reasons for the following:

    (i) PbO2 is a stronger oxidising agent than SnO2

    (ii) In solid state PCl5 behaves as an ionic species,

    (iii) Aluminium chloride (AlCl3) is very often used as a catalyst.

    (b) What is the structural difference between orthosilicates and pyrosilicates?

    OR

    (a) Assign reasons for the following:

    (i) The acid strengths of acids increase in the order

    HF < HCl < HBr < HI

    (ii) The lower oxidation state becomes more stable with increasing atomic number in Group 13.

    (iii) H3PO2 behaves as a monoprotic acid.

    (b) Draw the structures of the following compounds:

    (i) SF4

    (ii) XeF2

    VIEW SOLUTION
  • Question 27

    (a) Answer the following question briefly:

    (i) What are reducing sugars?

    (ii) What is meant by denaturation of a protein?

    (iii) How is oxygen replenished in our atmosphere?

    (b) Define enzymes.

    OR

    (a) Answer the following questions briefly:

    (i) What are any two good sources of vitamin A?

    (ii) What are nucleotides?

    (iii) Give an example of simple lipids.

    (b) How are carbohydrates classified?

    VIEW SOLUTION
More Board Paper Solutions for Class 12 Science Chemistry
What are you looking for?

Syllabus