Why does hg2+ have a negative standard entropy
(-32.2j. k-1mol-1) and hg
22+have a positive standard entropy
(84.5j. k-1mol-1)?

Hg∧2+ has a negative standard entropy because the ions are highly solvated in aqueous phase; smaller the ionic size, the more highly it is surrounded by solvated ions. Therefore it will be in highly ordered state hence the entropy decreases.

Hg2 ^2+ has a positive standard entropy because the ionic size of Hg^2+ is smaller than Hg2 ^2+, so therefore the Hg^2+ is highly solvated and that means that it is in highly ordered state.  Hg2 ^2+  is not highly solvated so it will have a positive entropy

Explanation:

The values of standard entropy of aqueous ions has a negative standard entropy because the ions are highly solvated in aqueous phase; smaller the ionic size, the more highly it is surrounded by solvated ions. Therefore it will be in highly ordered state hence the entropy decreases.

Hg2 ^2+ has a positive standard entropy because the ionic size of Hg^2+ is smaller than Hg2 ^2+, so therefore the Hg^2+ is highly solvated and that means that it is in highly ordered state.  Hg2 ^2+  is not highly solvated so it will have a positive entropy

the answer is 75.0%.