Gujarat University 2005 B.Sc Chemistry -IX - Question Paper

Seat No. : ____________
TB-03
Chemistry Paper-IX
Time : three Hours] [Total Marks : 70
Instructions : (1) All ques. carry equal marks.
(2) ans should be short and precise.
(3) Figure to the right shows the marks.
(4) Write accurate ques. number in the ans book.
Constants :
R = 1.987 cal/deg/mole = 8.314 joule/deg/mole
N = 6.02 × 1023 mole–1
F = 96500 coulomb
h = 6.623 × 10–27 erg/sec.
c = 3.0 × 1010 cm/sec = 3.0 × 108 m/sec.
1. (A) Derive the Vant Hoff formula relating the change in equilibrium constant with temperature. (5)
(B) Write a brief account on Trouton’s legal regulations. (5)
(C) The vapour pressures of water at 95°C and 100°C are 600 mm and 760 mm respectively. compute the latent heat of water. (4)
OR
(A) Derive an formula (5)
Kb = 0.002 T2bL? where Tb = boiling point of solvent
L? = latent heat of solvent
Kb = elevation constant
(B) Derive the Clapeyron-Clausius formula. explain the effect of pressure on melting point of ice. (5)
(C) The value of ?H of the subsequent reaction (4)
N2 + O2 ?? 2NO at 27°C
is 10.0 kilo.cal/mole and ?S = 0.1 cal/deg/mole. compute the equilibrium constant for the reaction.
2. (A) explain the various kinds of electrodes used in the measurement of emf. (5)
(B) What is liquid–liquid suction potential ? Derive the formula for that potential. How is the effect nullified ? (5)
TB-03 three P.T.O.
(C) At 25°C the electrode is kept in HCl solution. The cell is (4)
Pt · H2·HCl
HCl · H2
P = 0.2 atm
HCl
P = 1.0 atm
Pt.
compute the emf of the cell.
OR
2. (A) discuss the Pogendroff’s method used in determining the emf of a cell. Why ordinary voltmeter is not used for the measurement of emf ? (5)
(B) discuss in detail over-voltages and decomposition voltage. (5)
(C) The emf of the cell at 25°C (4)
Hg2 · Cl2
Pt · H2
Unknown
solution
Sat. KCl
Hg
is 0.714 volts. The emf of Calomel electrode is 0.212 volts. compute the pH of the unknown solution.
3. (A) explain the Florry-Huggins theory of polymer. (5)
OR
(A) Write any 1 method for determining the molecular weight of polymers. (5)
(B) elaborate salt effects ? discuss primary or secondary salt effects in detail. (5)
OR
(B) explain the activated complex theory of reaction rates. (5)
(C) explain the phase rule diagram for 1 component system. (4)
OR
(C) explain the azeotropic mixtures. (4)
4. (A) explain in detail any 1 method for detection of Isotopes. (5)
OR
(A) What is artificial nuclear reaction ? How does neutron work as a projectile particle in nuclear reaction ? (5)
(B) Write a note on Raman-Spectra or Ortho-Para Hydrogen. (4)
(C) provide a brief account on photolysis and chemiluminescence. (5)
5. Write any 2 : (14)
(1) Arrestion theory of corrosion.
(2) Fuel cell – How is the efficiency of the cell increased ?
(3) Recovery of Cu, Ag and Fe from wastage material.
(4) various kinds of Inhibitors.
(5) explain the use of dissolved oxygen in the corrosion of iron in neutral solution.
__________
TB-03 4

Earning:   Approval pending.