The statement that describes the entropy change of a gas reaction is that if there is an increase in the number of gas molecules then ∆S>0. That is option C.
What is entropy change?
Entropy change is defined as the change that occurs in a chemical reaction medium whereby the change of disorder or randomness in a thermodynamic system can be measured.
In a chemical reaction that involves only gas molecules:
A decrease in the number of moles on the product side means lower entropy.
An increase in the number of moles on the product side means higher entropy.
Therefore, the statement that describes the entropy change of a gas reaction is that if there is an increase in the number of gas molecules then ∆S>0.
