(Model Paper) Download 12th Class Model Paper ( CHEMISTRY )

SECTION A

Long Answer Type Questions:
Q.1. What is solubility? Explain the effect of temperature and pressure on the solubility of gases in liquids.
OR
What is colligative property? How is the molecular mass of a solute calculated from elevation in boiling point? 1 gms of a non-electrolyte solute dissolved in 50g of benzene lowered the freezing point of benzene by 0.40 K. The K_b value of benzene 5.12 KKgmol^-1. Find the molar mass of the solute. (5 marks)

Q.2. Why molar conductivity of weak electrolytes cannot be calculated from extrapolation method? Explain how the molar conductivity of weak electrolytes is  calculated from Kohlrauch’s law?
OR
Depict a galvanic cell in which the reaction is
Zn(s) + Cu²⁺(aq) ------>  Zn²⁺(aq) + Cu(s)
(i) Which of the electrodes is negatively charged?
(ii) What are the carriers of current in the cell?
(iii) What is the individual reaction at each electrode?
(iv) What are the functions of salt bridge? ( 5 marks )

Q.3. Name the oxoacids of Phosphorus. Predict their basicity form their structure. Which of the two H₃PO₃ and H₃PO₄ is stronger?
OR
What are interhalogens? How are they produced? Give the structure of IF₇. (5marks)
Q.4. How will you distinguish between?
(i) Ethanol and acetone
(ii) acetaldehyde and benzaldehyde
(iii) Tollen’s and Fehling’s test?
OR
Describe the following.
(i) Cannizaro’s reaction
(ii) Aldol condensation
(iii) Cross Aldol condensation (5marks)

SECTION B

Short Answer Type Questions:
Q.5. In a solid, there is defect due to missing of equal number of opposite ions from normal lattice site.
(i) Which type of point defect is it?
(ii) What are the effects of this defect on the density and stability of such solids?
(iii) Name a solid which can have such defect.(3 marks)

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