`(C_(6)H_(12))overset(HCl)rarr underset((C_(6)H_(13)Cl))(B)+(C )`
`(B)overset(Alc.KOH)rarr(D)` [isomer of (A)]

Explanation

To solve the problem, we need to analyze the reactions step by step based on the information provided.

### Step 1: Identify the starting compound
The starting compound is given as \( C_6H_{12} \). This molecular formula indicates that it is an alkene, specifically a hexene, since it follows the general formula for alkenes \( C_nH_{2n} \).

### Step 2: Determine the structure of the alkene
The simplest structure for hexene can be represented as:
- 1-Hexene: \( CH_2=CH-CH_2-CH_2-CH_2-CH_3 \)
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