Question

an exothermic reaction may not be always thermodynamically spontaneous. explain ​

Answer 1

Answer:

Exothermic reactions are generally thermodynamically spontaneous because even if it is accompanied by decrease of randomness ( e.g.,in the condensation of a gas or solidification ofa liquid), the heat releasedis absorbed by the surroundings so that the entropy of the surroundings increases to such an extent that

∆S total(+ve)

is positive. The molecules in the vapour state have greater freedom of movement and hence greater randomness than those in the liquid state. Hence, entropy increases in going from liquid to vapour state.

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