Question

An open vessel containing air is heated from 300K to 400K. The fraction of air, which goes out with respect to originally present is:

• A. 3/4
• B. 1/4
• C. 2/3
• D. 1/8

Answer 1

Answer: (B)

1/4

As the vessel is open, the pressure remains constant.

There is no change in the volume of the vessel. Hence, the volume also constant.

ACC to ideal gas equation, $PV=nRT$

$n_1+1T_1=300K$ $n_2=?T_2=400K$

$\frac{n_1}{n_2}=\frac{T_2}{T_1}$ (At constant P,V)

$\frac{1}{x}=\frac{400}{300}$

Fraction of air present in vessel after heating $=\frac{3}{4}.$

Fraction of air getting out of the vessel $=1-\frac{3}{4}=\frac{1}{4}$