What are the following:
Tollens' reagent

Explanation

### Step-by-Step Solution:

1. **Definition of Tollens' Reagent**:
Tollens' reagent is a chemical reagent used to detect the presence of aldehydes. It is a complex of silver, specifically represented as Ag(NH3)2^+.

2. **Composition**:
The reagent consists of silver ions (Ag^+) complexed with ammonia (NH3). The formula can be written as Ag(NH3)2^+.

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