What do you understand by tracers ? Give an example of a tracer that can be used in determining the mechanism of a chemical reaction.

Explanation

### Step-by-Step Solution:

1. **Definition of Tracers**:
A tracer, also known as a radiotracer, is a chemical compound in which one or more atoms have been replaced by a radionuclide. This substitution allows the compound to be tracked through a chemical reaction due to the radioactive properties of the radionuclide.

2. **Function of Tracers**:
The primary function of tracers is to trace the path of reactants as they undergo a chemical reaction to form products. By observing the behavior of the tracer, scientists can infer details about the mechanism of the reaction.

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