Choose the reaction with negative `DeltaS` value

Options

A. `2NaHCO_(3(s))rarrNa_(2)CO_(3(s))+CO_(2(g))+H_(2)O_((g))`
B. `Cl_(2(g))rarr2Cl_((g))`
C. `2SO_(2(g))+O_(2(g))rarr2SO_(3(g))`
D. `2KClO_(3(s))rarr2KCl_((s))+3O_(2(g))`

Answer

C

Explanation

`DeltaS` has negative value if `Deltan_(g)=-ve` i.e. number of gaseous moles decreasing during a reaction.
For (a), `Deltan_(g)=2-0=2`
For (b), `Deltan_(g)=2-1=1`
For (c ), `Deltan_(g)=2-3=-1` (`DeltaS` negative)
For (d), `Deltan_(g)=3-0=3`
For (e), `Deltan_(g)`=1-0=1