States of Matter - Result Question 46
####47. A gas is said to behave like an ideal gas when the relation $P V / T=$ constant. When do you expect a real gas to behave like an ideal gas?
(a) When the temperature is low
[1991]
(b) When both the temperature and pressure are low
(c) When both the temperature and pressure are high
(d) When the temperature is high and pressure is low
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Solution:
- (d) At low pressure and high temperature correction for 1 mole of a gas is negligible, i.e the effect of $a / v^{2}$ and $b$ becomes negligible.
Thus, the gas equation becomes
$P V=n R T$
$P V=R T$ or $\frac{P V}{R T}=1$ [Ideal gas equation]
$\therefore \quad Z=1$, and gas shows ideal behaviour.
