Chemical and Ionic Equilibrium - Result Question 84

####28. For a reaction, AP, the plots of [A] and [P] with time at temperatures T1 and T2 are given below.

If T2>T1, the correct statement(s) is are

(Assume ΔH and ΔS are independent of temperature and 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.)

(2018 Adv.)

(a) ΔH<0,ΔS<0

(b) ΔG<0,ΔH>0

(c) ΔG<0,ΔS<0

(d) ΔG<0,ΔS>0

Show Answer

Solution:

  1. For the reaction, AP

Given,

T1<T2 lnK1lnK2>T2T1

It shows, On increasing the temperature, K decreases so reaction is exothermic i.e., ΔH<0

Besides, graph shows K>1

So

ΔGo<0

Now from equation (i)

T1lnK1>T2lnK2 ΔGo>ΔGo  Likewise (ΔHo+T1ΔSo)>(ΔHo+T2ΔSo)  or simply T1ΔSo>T2ΔSo  So, (T2T1)ΔS<0 ΔSo<0

In other words, increase of ΔG with increase in temperature is possible only when ΔS<0. Hence, options (a) and (c) are correct.



जेईई के लिए मॉक टेस्ट

एनसीईआरटी अध्याय वीडियो समाधान

दोहरा फलक