The molar heat of vapourization of toluene is AHv. If its vapour pressure at 315 K is 60 torr & that at 356K is300 torr then AHv = ? (log 2 = 0.3)

(1) 37.5 kJ/mole

(2) 3.75 kJ/mole

(3) 37.5 J/mol

(4) 3.75 J/mole

Relative decrease in vapour pressure of an aqueous solution containing 2 moles [Cu(NH₃)₃Cl) Cl in 3 moles H₂O is 0.50. On reaction with AgNO₃, this solution will form (assuming no change in degree of ionisation of substance on adding AgNO₃)

(1) 1 mol AgCl

(2) 0.25 mol AgCl

(3) 0.5 mol AgCl

(4) 0.40 mol AgCl

Which of the following has been arranged in order of decreasing freezing point?

A solution of x moles of sucrose in 100 grams of water freezes at −0.2°C. As ice separated the freezing point goes down to 0.25°C. How many grams of ice would have separated?

1. 10 grams

2. 20 grams

3. 25 grams

4. 23 grams

An ideal mixture of liquids A and B with 2 moles of A and 2 moles of B has a total vapour pressure of 1 atm at a certain temperature. Another mixture with 1 mole of A and 3 moles of B has a vapour pressure greater than 1 atm. But if 4 moles of C are added to the second mixture, the vapour pressure comes down to 1 atm. Vapour pressure of C, P_c° = 0.8 atm. Calculate the vapour pressures of pure A and pure B.

(1) P_A° = 1.4 atm, P_B° = 0.7 atm

(2) P_A = 1.2 atm, P_B° = 0.6 atm

(3) P_A = 1.4 atm, P_B° = 0.6 atm

(4) P_A° = 0.6 atm, P_B° = 1.4 atm

A sample of air is saturated with benzene (vapor pressure = 100 mm Hg at 298 K) at 298K, 750mm Hgpressure. If it is isothermally compressed to one third of its initial volume, the final pressure of the system is

(1) 2250 torr

(2) 2150 torr

(3) 2050 torr

(4) 1950 torr

Available solutions are 1L of 0.1 M NaCl and 2L of 0.2 M CaCl₂. Using only these two solutions what maximum volume of a solution can be prepared having [Cl^–] = 0.34M exactly. Both electrolytes are strong

(1) 2.5 L

(2) 2.4 L

(3) 2.3 L

(4) None of these

Consider equimolal aqueous solutions of NaHSO₄ and NaCl with $∆$T_b and $∆T\text{'}$_b as their respective boiling point elevations. The value of $\underset{x\to 0}{\lim }\frac{\Delta T_b}{\Delta T_b^{\text{'}}}$ will be :

(1) 1

(2) 1.5

(3) 3.5

(4) 3

The vapor pressures of benzene, toluene and a xylene are 75 Torr, 22 Torr and 10 Torr at 20°C. Which of the following is not a possible value of the vapor pressure of an equimolar binary/ternary solution of these at 20°C ? Assume all form ideal solution with each other.

(1) 48$\frac{1}{2}$

(2) 16

(3) $35\frac{2}{3}$

(4) 53$\frac{1}{2}$

3.24 g of Hg(NO₃)₂ (molar mass = 324) dissolved in 1000 g of water constitutes a solution having a freezing point of –0.0558°C while 21.68 g of HgCl₂ (molar mass = 271) in 2000 g of water constitutes a solution with a freezing point of –0.0744°C. The K_f for water is 1.86 $\frac{\text{K\hspace{0.17em}– Kg}}{\text{Mol}}$. About the state of ionization of these two solids in water it can be inferred that:

(1) Hg(NO₃)₂ and HgCl₂ both are completely ionized

(2) Hg(NO₃)₂ is fully ionized but HgCl₂ is fully unionized

(3) Hg(NO₃)₂ and HgCl₂ both are completely unionized

(4) Hg(NO₃)₂ is fully unionized but HgCl₂ is fully ionized