Question

Pressure versus temperature graphs of an ideal gas are as shown in figure. Choose the wrong statement.

• A. Density of gas is increasing in graph (i).
• B. Density of gas is decreasing in graph (ii).
• C. Density of gas is constant in graph (iii).
• D. None of the above.

Answer 1

Answer: (C)

$\rho =\frac{PM}{RT}$
Density $\rho$ remains constant when $P/T$ or volume remains constant. In graph (i) volume is decreasing, hence density is increasing; while in graphs (ii) and (iii) volume is increasing, hence, density is decreasing.
The volume would have been constant in case the straight line in graph (iii) had passed through origin.