Determine which of the following reactions taking place at constant pressure represents system that do work on the surrounding environment
`Ag^(+)(aq)+Cl^(-)(aq)rarrAgCl(s)" " (II) NH_(4)Cl(s)rarrNH_(3)(g)+HCl(g) " " (III) 2NH_(3)(g)rarrN_(2)(g)+3H_(2)(g)`

Options

A. I
B. III
C. II and III
D. I and II

Answer

C

Explanation

`W=-Deltan_(g)RT=-ve`
`"II. " Deltan_(g)=2, " III. " Deltan_(g)=2`