What is positional isomerism? Give an example.

Explanation

### Step-by-Step Solution:

1. **Definition of Positional Isomerism**:
Positional isomerism is a type of structural isomerism where compounds have the same molecular formula and the same functional groups, but differ in the position of the functional group or substituent on the carbon chain.

2. **Understanding the Concept**:
In positional isomerism, the basic structure of the molecule remains the same, but the location of a specific functional group (like -OH, -NH2, etc.) changes. This leads to different compounds with distinct properties.

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