31.  When a gas is heated from 298K to 323K at a constant pressure of 1 atm its volume is

A. Increases from V to 1.8 V

B. Increases from V to 1.08 V

C. Increases from V to 1.5 V

D. Increases from V to 2 V

Explanation :

According to Charles’ law

$$\frac{V_{1}}{T_{1}}=\frac{V_{2}}{T_{2}}$$

$$\frac{V_{1}}{298}=\frac{V_{2}}{323}$$

$$\therefore V_{2}=\frac{323}{298}V_{1}$$

$$=1.08V_{1}$$

32.  At $$20^{\circ}C$$ and 760 torr, the sample of air contains 20% $$O_{2}$$ & 80% $$N_{2}$$ gaseous mixture, find the density of the air (Molarmass $$O_{2}$$ = 32 g/mol , $$N_{2}$$ = 28 g/mole R =0.082 $$liter\ mole^{-1}K^{-1}$$)

A. 1.918 $$gL^{-1}$$

B. 2.198 $$gL^{-1}$$

C. 1.198 $$gL^{-1}$$

D. 1.394 $$gL^{-1}$$

33.  The ratio of velocities of diffusion of gas A and B is 1 : 4, if the ratio of their masses in a mixture is 2:3, calculate the ratio of their mole fractions (BIT 1990)

A. 1 : 12

B. 1 : 24

C. 1 : 6

D. 4 : 3

34.  Under same conditions of temperature and pressure the volumes of 14g $$N_{2}$$ and 36g of $$O_{3}$$ are related as :

A. $$2V_{N_{2}}=3V_{O_{3}}$$

B. $$3V_{N_{2}}=2V_{O_{3}}$$

C. $$3V_{N_{2}}=4V_{O_{3}}$$

D. $$4V_{N_{2}}=3V_{O_{3}}$$

35.  Equal masses of Hydrogen and oxygen gases are placed in a closed container, at a pressure of 3.4 atm. The contribution of hydrogen gas to the total pressure is

A. 1.7 atm

B. 0.2 atm

C. 3.2 atm

D. 3.02 atm

36.  The kinetic energy of 4.0 moles of $$N_{2}$$ gas at $$127^{\circ}C$$ is $$\left ( R=2\ cal\ mole^{-1}K^{-1} \right )$$

A. 4400 cal

B. 3200 cal

C. 4800 cal

D. 1524 cal

37.  The critical temperature of $$H_{2}O$$ is higher than $$CO_{2}$$ because (IIT 1997)

A. fewer electrons than $$CO_{2}$$

B. It contains 2- covalent bonds

C. Molecular shape is V- shape

D. dipole moment of $$H_{2}O$$

38.  The compressibility factor of an ideal gas is

A. 0

B. 1

C. 2

D. 4

39.  A 10 L cylinder of nitrogen at 4.0 atm pressure and $$27^{\circ}C^{-}$$ developed a leak. When the leak was repaired 2.36 atm of nitrogen remained in the cylinder at $$27^{\circ}C$$. How many grams of nitrogen escaped?

A. 18.7g

B. 0.67g

C. 52.6g

D. 10.0g

40.  Calculate percentage of $$NO_{2}$$ by weight in $$N_{2}O_{4}$$ which has vapour density of 36.