Question

When disorder of a system increases, the changes are said to be
A. Exothermic
B. Non-spontaneous
C. Endothermic
D. Spontaneous

Answer 1

Hint: The second law of thermodynamics states that the entropy of the universe rises for an irreversible process.
It remains constant for a reversible process.

Complete step-by-step answer: Entropy is determined as the magnitude of disorderness in a state of a system.
It specifies the peculiarity or lack of consistency in the structure of a thermodynamic system.
This is indicated by ‘S’.
All the spontaneous processes are irreversible.
According to the second law of thermodynamics, the entropy of all spontaneous processes increases.
The greater the spontaneity in a system, the greater will be the degree of disorderness which will conclude in higher entropy.
For example-
Considering a thermodynamic system, the entropy of the liquid state is more than the entropy of the solid state.
Also, the entropy of the gas is more than the entropy of the liquid.
This is because the degree of disorderness is the highest in a gaseous state and lowest in a solid state.
The entropy of the liquid state is more than the solid state but less than the gaseous state.
So, entropy rises in the chemical reactions in which solid or liquid substrates react to form gaseous products.
Entropy is also enhanced when solid substances convert to liquid products.
For the dissolving of a solute in a solvent, the solute particles break down and enter the free space present in the solvent to form a solution.
Due to this the degree of disorderliness increases. Hence, as a result, entropy increases.

So, option D is correct.

Note: Entropy is a calculation of the extent of randomness or disorderliness of a system. A system intends to increase its entropy. The chemical reactions progress in a way to raise the total entropy of the system. The entropy of the universe is increasing.