Assertion (A): At 273 K the Z versus P curve for H2 lies entirely above Z = 1. Reason (R): For H2 at 273 K the term a/RT is smaller than b. Choose the correct option.

Both A and R are true and R is the correct explanation of A

Both A and R are true but R is not the correct explanation of A

JEE Advanced levelSingle correct optionDifficulty 3 of 3rg172

Assertion (A): At $273 K$ the $Z$ versus $P$ curve for $H X_{2}$ lies entirely above $Z = 1$ . Reason (R): For $H X_{2}$ at $273 K$ the term $a / RT$ is smaller than $b$ . Choose the correct option.

For

H X_{2}

a = 0.244

and

b = 0.0266

; at

273 K

a / RT = 0.244/22.41 = 0.0109

, which is less than

b

. The net correction

b - a / RT

is positive at all pressures, so

Z

stays above 1. R is the correct explanation.