devarshi-dt-logo

Question:

For a reaction, A⇌P, the plots of [A] and [P] with time at temperature T1 and T2 are given below. If T2 > T1, the correct statement(s) is/are: (Assume ΔH° and ΔS° are independent of temperature and the ratio of lnK at T1 to lnK at T2 is greater than T2/T1. Here H, S, G, and K are enthalpy, entropy, Gibbs energy, and equilibrium constant, respectively.)

ΔG°<0, ΔS°<0

ΔG°<0, ΔH°>0

ΔH°<0, ΔS°<0

ΔG°<0, ΔS°>0

Solution:

The correct options are
A ΔH°<0, ΔS°<0
C ΔG°<0, ΔS°<0
A⇌P given T2>T1
lnK1/lnK2 > T2/T1 ⇒ T1 lnK1 > T2 lnK2 ⇒ −ΔG°1 > −ΔG°2 ⇒ (−ΔH° + T1ΔS°) > (−ΔH° + T2ΔS°) ⇒ T1ΔS° > T2ΔS° ⇒ ΔS° < 0.