Carboxylic acid, although unreactive to alcohols, reacts in the presence of small amount of `conc. H_2 SO_4` or with `2-3 %` of `HCl` ?
`RCOOH + R'OH overset (H^(oplus)) hArr RCOOR' + H_2 O`
Which of the following statements is//are correct about the above reaction ?
(I) This reaction is called Fischer esterification reaction.
(II) The equilibrium is shifted to `R.H.S` if `H_2 O` is removed by azeotropic distillation with benzene.
(III) The reaction of `RCOCl` and `R'OH` to give ester `(RCOOR')` is irreversible and more feasible than esterification of `RCOOH`.
(IV) If the above esterification of `RCOOH` is carried out in excess of `R'OH`, the equilibrium is shifted to `R.H.S`.

Options

A. `(I),(II)`
B. `(I),(II),(III)`
C. `(I),(II),(IV)`
D. All

Explanation

To analyze the question regarding the reaction of carboxylic acids with alcohols in the presence of concentrated sulfuric acid or hydrochloric acid, we will evaluate each statement one by one.

### Step-by-Step Solution:

1. **Understanding the Reaction**:
The reaction between a carboxylic acid (RCOOH) and an alcohol (R'OH) in the presence of an acid catalyst (like concentrated H2SO4 or HCl) leads to the formation of an ester (RCOOR') and water (H2O). This process is known as Fischer esterification.

**Hint**: Remember that Fischer esterification is a key reaction in organic chemistry for forming esters from carboxylic acids and alcohols.

2. **Evaluating Statement I**:
The first statement claims that this reaction is called Fischer esterification. This is true, as the reaction indeed falls under this category.

**Hint**: Fischer esterification is characterized by the formation of an ester and water from a carboxylic acid and an alcohol.

3. **Evaluating Statement II**:
The second statement mentions that the equilibrium is shifted to the right (towards the formation of products) if water is removed by azeotropic distillation with benzene. This is also correct, as removing a product (water) from the equilibrium will shift the reaction towards the product side according to Le Chatelier's principle.

**Hint**: Le Chatelier's principle states that if a system at equilibrium is disturbed, it will shift in a direction that counteracts the disturbance.

4. **Evaluating Statement III**:
The third statement discusses the reaction of acyl chlorides (RCOCl) with alcohols to form esters. This reaction is indeed irreversible and more feasible than the esterification of carboxylic acids because acyl chlorides are more reactive due to the better leaving group (Cl-). Therefore, this statement is correct.

**Hint**: Acyl chlorides are more reactive than carboxylic acids due to the presence of a better leaving group, making the reaction proceed to completion.

5. **Evaluating Statement IV**:
The fourth statement states that if the esterification of RCOOH is carried out in excess R'OH, the equilibrium is shifted to the right. This is true as increasing the concentration of one reactant (R'OH) will shift the equilibrium towards the product side.

**Hint**: Increasing the concentration of reactants in an equilibrium reaction favors the formation of products.

### Conclusion:
All four statements (I, II, III, and IV) are correct regarding the Fischer esterification reaction and the conditions affecting its equilibrium.

**Final Answer**: All statements are correct.