The $Z$ versus $P$ curves of a gas are drawn at three temperatures $T_{1}$ , $T_{2}$ and $T_{3}$ . At $T_{1}$ the curve has a deep minimum, at $T_{2}$ a shallow minimum and at $T_{3}$ it rises monotonically from $Z = 1$ . The correct order of temperatures is

Answer: B

The depth of the minimum is governed by the attraction term

a / RT

, which decreases as

T

rises. A deep minimum means low

T

, a shallow one means higher

T

, and a monotonic rise means

T

is at or above the Boyle temperature. Hence

T_{3} > T_{2} > T_{1}