Entropy And Free Energy

Entropy is a measure of disorder or randomness in a system. A process in which disorder decreases will result in a decrease in entropy.

Let’s analyze each case:

1. A liquid crystallizes into a solid: Disorder decreases because a liquid is more disordered than a solid. Entropy decreases.
2. Temperature of a crystalline solid is raised from 0 K to 115 K: Entropy increases as the particles gain energy and vibrate more. Entropy increases.
3. : Gases are formed, so disorder increases. Entropy increases.
4. : Bonds are broken and atomic particles are formed, increasing randomness. Entropy increases.
5. : Number of gas molecules increases, leading to higher disorder. Entropy increases.

Correct Prediction:

Entropy decreases in: A liquid crystallizes into a solid

Entropy is indeed the measure of the disorder or randomness of a system, and it is related to the chaotic motion of particles in the system. Statement (C) is incorrect because it misrepresents the definition of entropy.
Thus, the correct answer is (C).