1. For the equilibrium :  LiCl.3NH_3(s) LiCl.NH_3(s) + 2NH₃ , K_p =9 atm² .At 40°C. A 5 litre vessel contains 0.1mole of LiCl.NH₃ . How many mole of NH₃
should be added to the flask at this temperature to derive the backward reaction for completion ?
a. 0.7137 mole
b. 0.7937 mole
c. 0.7837 mole
d. none of these
Ans : (3)



3 × 5 = n × 0.0821 × 313
n = 0.5837
i.e,. (a - 0.2) = 0.5837
Initial mole of NH₃
= a = 0.5837 + 0.2
= 0.7837 mole


2. A weak acid HA after treatment with 12mL of 0.1M strong base BOH has a pH of 5. At the end point, the volume of same base required is 26.6mL. K_a of acid is
a. 1.8×10^-5
b. 8.2×10^-6
c. 1.8×10^-6
d. 8.2×10^-5
Ans : (2)

K_a
= 8.219 × 10^-6 .


3. 0.1 millimole of CdSO₄ are present in 10 mL acid solution of 0.08 N HCl. Now H₂ S is passed to precipitate all the Cd²⁺ ions. The pH of the solution after filtering off precipitate, boiling of H₂ S and making the solution 100 mL by adding H₂ O is :
a. 2
b. 4
c. 6
d. 8
Ans : (1)



4. Assuming non change in volume, calculate the minimum mass of NaCl neccesary to dissolve 0.010mol AgCl in 100L solution.
a. 15 kg
b. 21 kg
c. 10 kg
d. 17 kg
Ans : (4)

5. 338 mL clear saturated solution of AgBrO₃ requires just 30.4 mL of H₂ S(g) at 23°C and 748 mm Hg to preciptate all the Ag⁺ ions into Ag₂ S. What will be K_SP of AgBrO₃ ?
a. 5.29×10^-5
b. 5.0×10^-3
c. 3.45×10⁶
d. 5.29×10^-1
Ans : (1)




6. For the following reaction what happens when at constant (T), the 4HNO₃ 4NO₂ + 2H₂ O + O₂ pressure of the flask is increased but simultaneously some amount of O₂ was added so as to maintain the partial pressure of H₂ O contant
.a. forward
b. backward
c. no change
d. data in sufficient
Ans : (4)



7. For the reaction R - X + OH^- ROH +X^- , the rate is give as :Rate = 5.0×10^-5 [R-X][OH^- ] + 0.20×10^-5 [R-X]. What percentage of R-X react by S_N 2 mechanism when [OH^- ] = 1.0×10^-2 M ?
a. 96.1%
b. 3.9%
c. 80%
d. 20%
Ans : (4)

8. Aniline is diazotized and the diazonium salt hydrolysed to yield phenol which is brominated to produce C₆ H₂ (Br₃ )OH. Calculate the mass of the final product obtained from 9.3g of aniline if the yield in the two steps is 45% and 70%(Atomic mass of Br = 80)
a. 1.04g
b. 10.43g
c. 14.89g
d. 23.17g
Ans : (2)



9. A sample of₅₃ I¹³¹ as iodide ion was adminstered to a patient in a carrier consisting of 0.10 mg of stable iodide ion. After 4 days 67.7% of initial radioactivity was detected in the thyroid gland of the patient. What mass of stable iodide ion had migrated to thyroid gland. t_1/2 for iodide ion = 8 days.
a. 95.8%
b. 72.3%
c. 90.8%
d. none
Ans : (1)



Thus, iodide ion left is 0.707 part of initially injected sample, however the rate decreases only 67.7% or 0.677 in 4 days, thus. If 0.707 is left then iodide ion migrated to thyroid = 1 Thus, 0.677 is left then iodide ion migrated to thyroid


or 95.8% of the iodide ion is migrated to gland.

10. The isotopic composition of rubidium is ⁸⁵ Rb - 72 percent and ⁸⁷ Rb -28 percent.⁸⁷ Rb is weakly radioactive and decay by^- -emission with a decay constant of 1.1×10^-11 per year. A sample of the mineral pollucite was found to contain 450mg Rb and 0.72 mg of ⁸⁷ Sr. Estimate the age of mineral pollution, stating any assumption made.
a. 5.202×10⁸ yr
b. 2×10⁵ yr
c. 1×10² yr
d. none
Ans : (1)




11. In the Lindemann theory of unimolecular reactions, it is shown that the apparent rate constant for such a reaction is where C is the concentration of the reactant, k₁ and are constants. Calculate the value of C for which k_app has 90% of its limiting value at C tending to infinitely large values, given = 9 × 10⁵ .
a. 10^-6 mole/litre
b. 10^-4 mole/litre
c. 10^-5 mole/litre
d. 5×10^-5 mole/litre
Ans : (3)




12. 1 g charcoal is placed in 100mL of 0.5 M CH₃ COOH to form an adsorbed mono-layer of acetic acid molecule and thereby the molarity of CH₃ COOH reduces to 0.49. Calculate the surface area of charcoal adsorbed by each molecule of acetic acid. Surface area of charcoal = 3.01×10² m² /g.
a. 1×10^-9 m²
b. 5×10^-19 m²
c. 1 × 10^-8 m²
d. none
Ans : (2)




13. Suppose we have a cube of 1.00 cm length. It is cut in all three directions, so as to produce eight cubes, each 0.50 cm on edge length. Then suppose these 0.50cm cubes are each subdivided into eight cubes 0.25cm on edge length, and so on. How many of these successive subdivisions are required before the cubes are reduced in size to colloidal dimensions (100 nm).
a. 13 subdivisions
b. 15 subdivisions
c. 19 subdivisions
d. 17 subdivisions
Ans : (4)
We find that every division in two equal halves also reduces the size of edge length to one half.
In first subdivision 1 cm is reduced to 0.5 cm In second subdivision 0.5cm is reduced to 0.25cm

14. AB, A₂ and B₂ are diatomic molecules. If the bond enthalpies of A₂ , AB and B₂ are in the ratio 1 : 1 : 0.5 and the ethalpy of formation of AB from A₂ and B₂ is -100 kJ mol^-1, what is the bond enthalpy of A₂
a. 400 kJ mol^-1
b. 200 kJ mol^-1
c. 100 kJ mol^-1
d. 300 kJ mol^-1
Ans : (1)

15. When 1 mole of crystalline NaCl is obtained from sodium and chlorine gas, 410 kJ of heat is released. The heat of sublimation of Na metal is 108 kJ mol^-1
and Cl-Cl bond enthalpy is 242 kJ mol^-1 . If the ionisation energy of Na is 493.0 kJ mol^-1 and the electron affinity of chlorine is 368 kJ mol^-1 , the lattice energy of NaCl is
a. 764 kJ mol^-1
b. -744 kJ mol^-1
c. 885 kJ mol^-1
d. -885 kJ mol^-1
Ans : (2)

16. The enthalpy of neutralisation of a weak acid in 1M solution with a strong base is -56.1 kJ mol^-1 . If the enthalpy of ionization of the acid is 1.5 kJ mol^-1
and enthalpy of neutralisation of the strong acid with a strong base is -57.3 kJ equiv^-1 , what is the % ionization of the weak acid in molar solution (assume the acid to be monobasic) ?
a. 10
b. 15
c. 20
d. 25
Ans : (3)



17. A mineral having the formula AB₂ crystallises in a cubic close packed lattice, with A atoms occupying the lattice points. The co-ordination number of A atoms, that of B atoms and fraction of tetrahedral voids occupied by B atoms are respectively
a. 8,4,100%
b. 2,6,75%
c. 3,1,25%
d. 6,6,50%
Ans : (1)
The structures of AB₂ refers to fluorite type structure


18. In a compound XY₂ O₄ , oxide ions are arranged in ccp and cations X are present in octahedral voids. Cations Y are equally distributed between octahedral and tetrahedral voids. The fraction of the octahedral voids occupied is
a. 1/2
b. 1/4
c. 1/8
d. 1/6
Ans : (1)
Four oxide ions arranged in CCP would have four octahedral voids associated with them. Out of these four voids one is occupied by X and one by Y. So, 2 voids out of 4 are occupied. So 1/2 is the answer.


19. What is the packing fraction of the two dimensional unit cell shown in figure.


a. 0.92
b. 0.74
c. 0.5234
d. none
Ans : (1)
packing fraction

20. In the vapour phase acetic acid molecule associate to the some extent to form dimers. At 50°C, the pressure of a certain acetic acid vapours is 0.0342 atm in a 360mL flask. The vapour is condensed and neutralized with 13.8mL 0.0568M NaOH. Calculate the degree of dissociation of the dimer.
a. 0.84
b. 0.94
c. 1.72
d. none of these
Ans : (1)



21. The concentration of CO₂ is expected to rise 440 ppm in year 2020. What would be the pH of rainwater in the year 2020 if molar solubility of CO₂ is 0.0343 L^-1 bar^-1 . Ka1 of CO₂ = 4.2×10^-7 .
a. 5.63
b. 4.72
c. 5.063
d. none of these
Ans : (1)



22. 1.0 metric ton coal containing 2.5% sulphur is burned and SO₂ produced in the combustion was dissolved in rainwater of volume equivalent to 2.0cm rain fall over 2.6km² area. Determine pH of rainwater if K_a of H₂ SO₃ = 1.5×10^-2 .
a. 4.8
b. 4.08
c. 0.48
d. none of these
Ans : (1)