Arrange the following halides in order increasing `S_(N^(2))` reactivity `CH_(3)Cl,CH_(3)Br,CH_(3)CH_(2)Cl,(CH_(3))_(2)CHCl`.

Explanation

To arrange the given halides in order of increasing SN2 reactivity, we need to consider the structure of each compound and the factors that influence SN2 reactions. The key factors are the nature of the leaving group and the steric hindrance around the carbon atom that is attached to the halogen.

### Step-by-Step Solution:

1. **Identify the Halides**: The halides given are:
- CH₃Cl (Methyl chloride)
- CH₃Br (Methyl bromide)
- CH₃CH₂Cl (Ethyl chloride)
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