For a reaction at 25∘C enthalpy change (△H) and entropy change (△S) are −11.7×103Jmol−1 and −105Jmol−1K−1 respectively. Find out whether this reaction is spontaneous or not?
Non-spontaneous
For checking spontaneity, we need to check the value of △G.
If △G = -ve → spontaneous
△G = +ve → Non-spontaneous
Given, △H = −11.7×103Jmol−1
△S = −105Jmol−1K−1
T = 298 K
∴△G = △H - T△S = −11700−298×(−105) = 19590 J = + 19.59 kJ
Since △G = +ve
∴reaction is not spontaneous.