Isobutylene on hydroboration followed by reaction with `H_(2)O_(2) /OH^(–)` –

Options

A. Primary alcohol
B. Secondary alcohol
C. Tertiary alcohol
D. Dihydric alcohol

Answer

To solve the question regarding the hydroboration of isobutylene followed by oxidation with \( H_2O_2/OH^- \), we will follow these steps:

### Step 1: Draw the structure of Isobutylene
Isobutylene, also known as 2-methylpropene, has the following structure:

\[ \text{CH}_2=C(CH_3)\text{CH}_3 \]

### Step 2: Perform Hydroboration
In the hydroboration step, isobutylene reacts with diborane (\( B_2H_6 \)) to form a trialkylborane intermediate. The reaction follows the anti-Markovnikov addition rule, meaning that the boron atom will attach to the less substituted carbon atom (the carbon with more hydrogen atoms).

The intermediate formed after hydroboration can be represented as:

\[ \text{CH}_3-CH(BH_2)-CH_3 \]

### Step 3: Oxidation with \( H_2O_2/OH^- \)
In the oxidation step, the trialkylborane intermediate reacts with hydrogen peroxide (\( H_2O_2 \)) in the presence of hydroxide ions (\( OH^- \)). The \( OH^- \) acts as a nucleophile and replaces the \( BH_2 \) group with a hydroxyl group (\( OH \)).

The product after oxidation will be:

\[ \text{CH}_3-CH(OH)-CH_3 \]

### Step 4: Determine the Degree of Alcohol
The product formed is 2-propanol (isopropanol), which is a secondary alcohol. This is determined by the fact that the carbon atom bearing the \( OH \) group is attached to two other carbon atoms.

### Final Structure
The final structure of the product is:

\[ \text{CH}_3-CH(OH)-CH_3 \]

### Conclusion
The final product of the hydroboration of isobutylene followed by oxidation with \( H_2O_2/OH^- \) is 2-propanol, which is a secondary alcohol.

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