Give the equation for the formation of main product when hydrogen iodide is added to isobutylene.

Explanation

To solve the problem of determining the main product formed when hydrogen iodide (HI) is added to isobutylene (2-methylpropene), we will follow these steps:

### Step 1: Identify the Structure of Isobutylene
Isobutylene is an alkene with the following structure:
\[ \text{CH}_2 = \text{C}(\text{CH}_3) - \text{CH}_3 \]
This can also be represented as:
\[ \text{C}_4\text{H}_8 \]

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