The process with negative entropy change is

Options

A. Synthesis of ammonia from `N_(2)` and `H_(2)`
B. Dissociation of `CaSO_(4)` (s) to CaO(s) and `SO_(3)`(g)
C. Subimation of dry ice
D. Dissolution of iodine in water

Answer

A

Explanation

(A) `N_(2) + 3H_(2) to 2NH_(3)`
Since, number of gaseous moles are decreasing hence entropy `DeltaS =S_("products")-S_("reactants")` is negative
(B) `underset(s)(CaSO_(4)) to underset(B)(CaO) + underset(g)(SO_(3))`
`DeltaS`: positive, as number of gas moles increases
( C) `CO_(2) (s) to CO_(2)(g)`
`DeltaS`: positive as number of gaseous moles are increasing
( D) `I_(2)(g) to I_(2)(aq)`
`DeltaS`: positive as randomness of the system has increased