Answer:
D. H₂O (g) → H₂O (l)
Explanation:
Entropy is a measure of "disorder". Gases have more entropy than liquids, which have more entropy than solids.
a) The number of moles of gas increases from 2 to 3, so entropy increases.
b) The number of moles of gas increases from 1 to 2, so entropy increases.
c) The solid becomes a gas, so entropy increases.
d) The gas becomes a liquid, so entropy decreases.
