The van't Hoff factor, i for a compound which undergoes dissociation in one solvent and

association in other solvent is respectively.

1. less than one and less than one

2. greater than one and less than one

3. greater than one and greater than one

4. less than one and greater than one

0.5 molal aqueous solution of a weak acid (HX) is 20% ionised. If K_f for water is 1.86 K kg mol^-1, the lowering in freezing point of the solution is:

(1) -1.12 K

(2) 0.56 K

(3) 1.12 K

(4) - 0.56 K

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

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  

A 500 gm toothpaste sample has 0.2 g fluoride concentration. The concentration of fluoride ions in terms of ppm level is

(1) 250 ppm

(2) 200 ppm

(3) 400 ppm

(4) 1000 ppm

Amount of NaOH present in 200 ml of 0.5 N solution is 

(1) 40 g

(2) 4 g

(3) 0.4 g

(4) 4.4 g

10.6 g of Na₂CO₃ was exactly neutralised by 100 ml of H₂SO₄ solution. Its normality is

(1) 1 N

(2) 2 N

(3) 1.5 N

(4) 0.5 N

Equal volumes of $0.1\mathrm{M}{\mathrm{AgNO}}_3$ and 0.2 M NaCl are mixed. The concentration of ${\mathrm{NO}}_3^{-}$ ions in the mixture will be 

(1) 0.1 M

(2) 0.05 M

(3) 0.2 M

(4) 0.15 M

If 20 ml of 0.4 N NaOH solution completely neutralises 40 ml of dibasic acid. The molarity of acid solution is

(1) 0.1 M

(2) 0.2 M

(2) 0.3 M

(4) 0.4 M