Base hydrolysis of an ester with NaOH gives a carboxylic acid whose sodium salt on Kolbe's electrolysis yields ethane. The ester is

Options

A. ethyl methanoate
B. methyl ethanoate
C. phenyl benzoate
D. ethyl propanoate

Explanation

To solve the problem, we need to identify the ester that undergoes base hydrolysis to yield a carboxylic acid whose sodium salt can produce ethane upon Kolbe's electrolysis. Let's break it down step by step.

### Step 1: Understanding Base Hydrolysis of Esters
When an ester undergoes base hydrolysis with sodium hydroxide (NaOH), it produces a carboxylic acid and an alcohol. The general reaction can be represented as:
\[ \text{RCOOR'} + \text{NaOH} \rightarrow \text{RCOO}^- \text{Na}^+ + \text{R'OH} \]
Where RCOOR' is the ester, RCOO^- Na^+ is the sodium salt of the carboxylic acid, and R'OH is the alcohol.

### Step 2: Kolbe’s Electrolysis
Kolbe's electrolysis involves the electrolysis of the sodium salt of a carboxylic acid. During this process, the carboxylate ion (RCOO^-) can lose CO2 and form an alkane. The reaction can be summarized as:
\[ 2 \text{RCOO}^- \rightarrow \text{R-R} + 2 \text{CO}_2 + 2 \text{e}^- \]
Here, R-R represents the alkane formed.

### Step 3: Identifying the Product
The problem states that the Kolbe's electrolysis yields ethane (C2H6). This indicates that the R group in the carboxylic acid must be a methyl group (CH3), because:
\[ \text{CH}_3\text{CH}_3 \text{ (ethane)} \]
This means the carboxylic acid must be acetic acid (ethanoic acid), which has the structure:
\[ \text{CH}_3\text{COOH} \]

### Step 4: Finding the Corresponding Ester
To find the ester that would yield acetic acid upon hydrolysis, we can consider the ester formed from acetic acid and an alcohol. The simplest ester that fits this description is methyl acetate (methyl ethanoate), which has the structure:
\[ \text{CH}_3\text{COOCH}_3 \]

### Step 5: Verification
1. **Base Hydrolysis of Methyl Acetate:**
\[ \text{CH}_3\text{COOCH}_3 + \text{NaOH} \rightarrow \text{CH}_3\text{COO}^- \text{Na}^+ + \text{CH}_3\text{OH} \]
This produces sodium acetate (CH3COONa) and methanol (CH3OH).

2. **Kolbe’s Electrolysis of Sodium Acetate:**
\[ 2 \text{CH}_3\text{COO}^- \rightarrow \text{C}_2\text{H}_6 + 2 \text{CO}_2 + 2 \text{e}^- \]
This confirms that sodium acetate can yield ethane upon Kolbe's electrolysis.

### Conclusion
The ester that undergoes base hydrolysis to yield a carboxylic acid whose sodium salt produces ethane upon Kolbe's electrolysis is **methyl acetate (methyl ethanoate)**.