Correct order of relative rates of esterfication of the following acids with MeOH is : `Me-COOH " " nPr-COOH " " Me_(3)C-COOH " " Et_(3)C-COOH`

Options

A. `P gt Q gt R gt S`
B. `Q gt R gt S gt P`
C. `S gt P gt Q gt R`
D. `S gt R gt Q gt P`

Explanation

To determine the correct order of relative rates of esterification of the given carboxylic acids with methanol (MeOH), we need to consider the steric hindrance associated with each acid. The acids provided are:

1. Me-COOH (Methyl carboxylic acid)
2. nPr-COOH (n-Propyl carboxylic acid)
3. Me₃C-COOH (Tert-butyl carboxylic acid)
4. Et₃C-COOH (Tert-pentyl carboxylic acid)

### Step-by-Step Solution:

**Step 1: Understand Esterification**
Esterification is the reaction between a carboxylic acid and an alcohol to form an ester and water. The rate of this reaction is influenced by the steric hindrance around the carboxylic acid.

**Step 2: Analyze Steric Hindrance**
Steric hindrance refers to the crowding around the reactive site, which can slow down the reaction. The more bulky groups attached to the carboxylic acid, the higher the steric hindrance, and thus the lower the rate of esterification.

**Step 3: Compare the Acids**
- **Me-COOH**: Has a methyl group (smallest) → Least steric hindrance.
- **nPr-COOH**: Has a propyl group → Moderate steric hindrance.
- **Me₃C-COOH**: Has three methyl groups attached to the carbon → High steric hindrance.
- **Et₃C-COOH**: Has three ethyl groups attached to the carbon → Highest steric hindrance.

**Step 4: Determine the Order of Esterification**
Based on the analysis of steric hindrance:
- **Me-COOH** will react the fastest due to the least steric hindrance.
- **nPr-COOH** will be slower than Me-COOH but faster than the others.
- **Me₃C-COOH** will be slower than nPr-COOH due to increased steric hindrance.
- **Et₃C-COOH** will react the slowest because it has the most steric hindrance.

**Final Order of Esterification:**
1. Me-COOH (Fastest)
2. nPr-COOH
3. Me₃C-COOH
4. Et₃C-COOH (Slowest)

### Conclusion:
The correct order of relative rates of esterification of the acids with MeOH is:
**Me-COOH > nPr-COOH > Me₃C-COOH > Et₃C-COOH**