The relative order of rate of esterification of acids for `1^0,2^0,3^0` is

Answer

To determine the relative order of the rate of esterification of carboxylic acids with 1°, 2°, and 3° alcohols, we need to consider the effect of steric hindrance on the reaction mechanism involved in esterification. Here’s a step-by-step solution:

### Step 1: Understand the Mechanism of Esterification
Esterification is a nucleophilic acyl substitution reaction where an alcohol reacts with a carboxylic acid to form an ester and water. The mechanism involves the following key steps:
1. Protonation of the carbonyl oxygen of the carboxylic acid.
2. Nucleophilic attack by the alcohol on the carbonyl carbon.
3. Formation of a tetrahedral intermediate.
4. Loss of a water molecule and regeneration of the carbonyl group to form the ester.

### Step 2: Analyze Steric Hindrance
The rate of esterification is influenced by steric hindrance around the carbonyl carbon of the carboxylic acid and the hydroxyl carbon of the alcohol. As the degree of substitution (1°, 2°, or 3°) increases, steric hindrance also increases.

- **1° Alcohols**: These have the least steric hindrance, allowing for easier access to the carbonyl carbon of the acid. Thus, they react faster.
- **2° Alcohols**: These have moderate steric hindrance, making the reaction slower than with 1° alcohols.
- **3° Alcohols**: These have the greatest steric hindrance, significantly slowing down the reaction due to difficulty in accessing the carbonyl carbon.

### Step 3: Establish the Order of Reactivity
Based on the analysis of steric hindrance:
- **1° Alcohols** > **2° Alcohols** > **3° Alcohols**

Thus, the relative order of the rate of esterification of acids with 1°, 2°, and 3° alcohols is:
**1° > 2° > 3°**

### Final Answer
The relative order of the rate of esterification of acids for 1°, 2°, and 3° is:
**1° > 2° > 3°**

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