11.  A mixture contains $$N_{2}O_{2}$$ and $$NO_{2}$$ in the ratio 2 : 1 by volume. The vapour density of the mixture is

A. 45.4

B. 49.8

C. 32.6

D. 38.3

12.  At extremely low pressure, the van der waals equation for one mole of a gas may be written as

A. $$PV=RT+pb$$

B. $$PV=RT-\frac{a}{v}$$

C. $$PV=RT$$

D. $$\left ( p+\frac{a}{v} \right )(v-b)=RT$$

13.  The compressibility of a gas is less than unity at STP Therefore

A. $$V_{m} > 22.4\ L$$

B. $$V_{m} < 22.4\ L$$

C. $$V_{m} = 22.4\ L$$

D. $$V_{m} = 44.8\ L$$

14.  The correct order for magnitude of van der waals constant b should be

A. $$C_{2}H_{6} < CO < CO_{2} < He$$

B. $$CO < C_{2}H_{6} < He < CO_{2}$$

C. $$C_{2}H_{6} < CO_{2} < CO < He$$

D. $$He < CO < CO_{2} < C_{2}H_{6}$$

15.  The molecular radius of $$O_{2}$$ is $$2.88\times 10^{-10}\ m$$ calculate the excluded volume per mol of $$O_{2}$$

A. $$0.24\ dm^{3}$$

B. $$0.48\ dm^{3}$$

C. $$0.024\ dm^{3}$$

D. $$0.048\ dm^{3}$$

16.  An ideal gas can not be liquefied because

A. The inter molecular force of attraction between the gaseous molecules are negligible.

B. Its critical temperature is very high

C. The van der waals constants a and b are very high

D. All of these

17.  The values of ‘a’ for the gases $$O_{2}$$, $$CO_{2}$$, $$N_{2}$$ and $$CH_{4}$$ are respectively 1.36, 3.64, 1.39 and 2.253 $$L^{2}\ atm\ mol^{-1}$$ which gas can be most easily liquefied ?

A. $$O_{2}$$

B. $$CO_{2}$$

C. $$N_{2}$$

D. $$CH_{4}$$

18.  The rate of diffusion of $$H_{2}$$ is about

A. 0.5 times that of He

B. 1.4 times that of He

C. Twice that of He

D. 4 times that of He

19.  Most probable speed, average speed, and RMS (root mean square speed) are related as

A. 1 : 1.224 : 1.128

B. 1.128 : 1 :1.224

C. 1 : 1.128 : 1.224

D. 1.224 : 1.128 : 1.0

20.  At room temperature the mixture of $$SO_{2}$$ and $$O_{2}$$ gas, compared to the $$O_{2}$$ molecule, the $$SO_{2}$$ molecule will hit the wall with