Answer
Acid: $Ag^+$
Base: $NH_3$
Work Step by Step
1. Determine if each compound can act as a Lewis acid, base or both.
- $Ag^+$: It is a transition metal cation, therefore, it is likely to behave as a Lewis acid.
- $NH_3$: The nitrogen has 2 electrons that aren't being used, therefore, it can act as a Lewis base.
2. So, we only have one option for this reaction:
$Ag^+$ as an acid and $NH_3$ as a base.
