Which is/are corect statement ?

Options

A.
B.
C. `This is only affected in reduction to `2^@` alcohol
D.

Answer

To determine which statements are correct regarding the reactions involving ethers and alcohols, we will analyze each statement step by step based on the information provided in the video transcript.

### Step-by-Step Solution:

1. **Analyze Statement A**:
- The statement discusses a reaction occurring in the presence of acid, favoring the SN1 mechanism.
- In SN1 reactions, the nucleophile attacks the more substituted carbon due to carbocation stability.
- The mechanism involves the formation of a carbocation after the leaving group departs.
- Since the nucleophile attacks from the more substituted side, this statement is **correct**.

2. **Analyze Statement B**:
- This statement involves a reaction in the presence of NaOH, which is a base, favoring the SN2 mechanism.
- In SN2 reactions, the nucleophile attacks from the less hindered side to avoid steric hindrance.
- If the statement claims that the nucleophile will attack from the more hindered side, it is **incorrect**.

3. **Analyze Statement C**:
- This statement involves the reduction of a carbonyl compound using NaBH4.
- NaBH4 is a mild reducing agent that can reduce aldehydes and ketones but not esters.
- The statement claims that NaBH4 will only reduce the carbonyl carbon and not the ester, which is **correct**.

4. **Analyze Statement D**:
- This statement describes the reaction between an acid and an alcohol in the presence of acid (H+), leading to ester formation.
- The mechanism involves protonation of the alcohol, followed by nucleophilic attack and subsequent bond cleavage.
- The statement correctly describes the cleavage of the acid and alcohol, indicating that the OH group comes from the acid and the H from the alcohol.
- Therefore, this statement is also **correct**.

### Conclusion:
The correct statements are A, C, and D. Statement B is incorrect.

### Summary of Correct Statements:
- **A**: Correct (SN1 mechanism favors attack at the more substituted carbon in the presence of acid).
- **B**: Incorrect (SN2 mechanism favors attack at the less hindered side in the presence of a base).
- **C**: Correct (NaBH4 reduces carbonyls but not esters).
- **D**: Correct (the reaction between acid and alcohol leads to ester formation with proper bond cleavage).