A certain hydrate has the formula ${\mathrm{MgSO}}_4.$ ${\mathrm{xH}}_2\mathrm{O}$. A quantity of 54.2 g of the compound is heated in an oven to drive off the water. If the water vapour generated exerts a pressure of 24.8 atm in a 2.0 L container at 120$°\mathrm{C}$, the value of x is-

1.  2

2.  5

3.  6

4.  7

The correct order of temperature of a real gas is-

I. Boyle's temperature

II. Critical temperature

III. Inversion temperature

1.  III > I > II

2.  I > II > III

3.  II > I > III

4.  I > III > II

A mixture of He and Ar weighting 5.0 g occupies a volume of $10$ ${\mathrm{dm}}^3$ $\mathrm{at}$ $27°\mathrm{C}$ and 1 atm pressure. The composition of the mixture is respectively -

1. 70%, 30%

2. 25%,75%

3. 75%,25%

4. 40%,60%

The density of a gaseous substance at 1 atm pressure and 773 K is 0.4 g/L. If the molecular weight of the substance is 30, the dominant force existing among gas molecules is/are-

1. Repulsive

2. Attractive

3. Both (1) & (2)

4. None of these

Van der Waals equation at low pressure is -

1. PV = RT - Pb

2. PV = RT - $\frac{\mathrm{a}}{\mathrm{V}}$

3. PV = RT + $\frac{\mathrm{a}}{\mathrm{v}}$

4. PV = RT + Pb

For one mole of van der Waal's gas when b=0 and T=300 K, the PV vs. 1/V plot is shown below.

The value of the van der Waal's constant 'a' (atm. ${\mathrm{litre}}^2$ ${\mathrm{mol}}^{-2}$) is-

1. 1.0

2. 4.5

3. 1.5

4. 3.0

At 298 K, assuming ideal behaviour, the average kinetic energy of a deuterium molecule is -

1. Two times that of a hydrogen molecule

2. Four times that of a hydrogen molecule

3. Half of that of a hydrogen molecule

4. Same as that of a hydrogen molecule

At room temperature, the average speed of Helium is higher than that of Oxygen by a factor of -

1. $2\sqrt{2}$

2. $6/\sqrt{2}$

3. 8

4. 6

In water-saturated air, the mole fraction of water vapor is 0.02. If the total pressure of the saturated air is 1.2 atm, the partial pressure of dry air is-

1. 1.17 atm

2. 1.76 atm

3. 1.27 atm

4.  0.98 atm

The volume occupied by 1.8 g of water vapour at 374 ${}^{\mathrm{o}}\mathrm{C}$ and 1 bar pressure will be -

[Use R=0.083 bar ${\mathrm{LK}}^{-1}$ ${\mathrm{mol}}^{-1}$]

1. 96.66 L

2. 55.87 L

3. 3.10 L

4. 5.31 L