A sample of liquid ${\mathrm{H}}_2\mathrm{O}$ of mass 18.0 g is injected into an evacuated 7.6 L flask maintained at 27.0$°$C. If vapour pressure of ${\mathrm{H}}_2\mathrm{O}$ at 27$°$C is 24.63 mm Hg. What weight percentage of the water will be vapourised when the system comes to equilibrium? Assume water vapours behave as an ideal gas. The volume occupied by the liquid water is negligible compared to the volume of the container :

1. 1%

2. 10%

3. 18%

4. 20%

The equal weight of a solute is dissolved in an equal weight of two solvents A and B to form a very dilute solution. The relative lowering of vapour pressure for solution B has twice the relative lowering of vapour pressure for solution A.

If ${\mathrm{M}}_{\mathrm{A}}$ and ${\mathrm{M}}_{\mathrm{B}}$ are the molecular weights of solvents A and B respectively, then:

1. ${\mathrm{M}}_{\mathrm{A}}$ = ${\mathrm{M}}_{\mathrm{B}}$

2. ${\mathrm{M}}_{\mathrm{B}}$ = 2${\mathrm{M}}_{\mathrm{A}}$

3. ${\mathrm{M}}_{\mathrm{A}}$ = 4${\mathrm{M}}_{\mathrm{B}}$

4. ${\mathrm{M}}_{\mathrm{A}}$ = 2${\mathrm{M}}_{\mathrm{B}}$

Calculate the percentage degree of dissociation of an electrolyte ${\mathrm{XY}}_2$ (Normal molar mass = 164) in water if the observed molar mass by measuring elevation in boiling point is 65.6:

1. 75%

2. 25%

3. 65%

4. None of these

The temperature of a city was found to be -9.3 °C. A car was used, whose radiator was filled with 5 L of water. What quantity of anti-freezing agent ethylene glycol was added to the water radiator in order to use the car for traveling? (${\mathrm{K}}_{\mathrm{r}}$ of water 1.86 K kg ${\mathrm{mol}}^{-1}$)

1. 3200 g

2. 1670 g

3. 1550 g

4. 2100 g

At 300 K, 40 mL of ${\mathrm{O}}_3$ (g) dissolved in 100 g of water at 1.0 atm. What mass of ozone dissolved in 400 g of water at a pressure of 4.0 atm at 300 K?

1. 0.1 g

2. 1.2 g

3. 0.48 g

4. 4.8 g

A saturated solution of ${\mathrm{XCl}}_3$ has a vapor pressure of 17.20 mm Hg at 20°C, while pure water vapor pressure is 17.25 mm Hg. Solubility product (${\mathrm{K}}_{\mathrm{sp}}$) of ${\mathrm{XCl}}_3$ at 20°C

1. 9.8x${10}^{-2}$

2. ${10}^{-5}$

3. 2.56x${10}^{-6}$

4. 7x${10}^{-5}$

A certain non-volatile electrolyte contains 40% carbon, 6.7% hydrogen, and 53.3% oxygen. An aqueous solution containing 5% by mass of the solute boils at 100.15°C. The molecular formula of the compound is:
(${\mathrm{K}}_{\mathrm{b}}$ = 0.51°C/m)

1. HCHO

2. ${\mathrm{CH}}_3\mathrm{OH}$

3. ${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}$

4. ${\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6$

0.1 M KI and 0.2 M ${\mathrm{AgNO}}_3$ are mixe in a 3:1 volume ratio. The depression of the freezing point of the resulting solution will be [${\mathrm{k}}_{\mathrm{r}}\left({\mathrm{H}}_2\mathrm{O}\right)$ = 1.86 K kg ${\mathrm{mol}}^{-1}$]

1. 3.72 K

2. 1.86 K

3. 0.93 K

4. 0.279 K.

The density of dry air containing only ${\mathrm{N}}_2$ and ${\mathrm{O}}_2$ is 1.15 g/L at 740 mm and 300 K. What is % composition of ${\mathrm{N}}_2$ by weight in the air:

1. 78%

2. 75.5%

3. 70.08%

4. 72.25%

The latent heat of vaporisation of water is 540 cal $g^{-1}$at $100°C$. K_b for water is

1. $0.562<mspace\; width="1em"></mspace>K.mol{e}^{-1}<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>$

2. $1.86<mspace\; width="1em"></mspace>K.mol{e}^{-1}<mspace\; width="1em"></mspace>$

3. $0.515<mspace\; width="1em"></mspace>K.mol{e}^{-1}$

4. $<mspace\; width="1em"></mspace>5.12<mspace\; width="1em"></mspace>K.mol{e}^{-1}$