Which of the following reactions will yield propan-2-ol ? Select the right answer from (a), (b), (c) and (d)
I. `CH_(2)=CH-CH_(3)+H_(2)O overset(H^(+))(rarr)`
II. `CH_(3)-CHO overset(CH_(3)MgI//H_(2)O)(rarr)`
III. `CH_(2)O underset(H_(2)O)overset(C_(2)H_(5)MgI)(rarr)`
IV. `CH_(2)=CH-CH_(3) overset("Neutral "KMnO_(4))(rarr)`

Options

A. I and II
B. II and III
C. III and I
D. II and IV

Answer

To determine which of the given reactions will yield propan-2-ol, let's analyze each reaction step by step.

### Step 1: Analyze Reaction I
**Reaction I:** \( CH_2=CH-CH_3 + H_2O \overset{H^+}{\rightarrow} \)

1. The alkene \( CH_2=CH-CH_3 \) undergoes hydration in the presence of an acid (H+).
2. The double bond opens up and a carbocation is formed on the more substituted carbon.
3. Water (H2O) attacks the carbocation, leading to the formation of an alcohol.
4. After deprotonation, the product formed is \( CH_3CHOHCH_3 \), which is propan-2-ol.

**Conclusion:** Reaction I yields propan-2-ol.

### Step 2: Analyze Reaction II
**Reaction II:** \( CH_3CHO \overset{CH_3MgI/H_2O}{\rightarrow} \)

1. The aldehyde \( CH_3CHO \) reacts with the Grignard reagent \( CH_3MgI \).
2. The nucleophilic carbon of the Grignard reagent attacks the carbonyl carbon of the aldehyde.
3. This results in the formation of a tertiary alcohol after hydrolysis with water.
4. The product formed is \( CH_3CO-CH_3 \) and upon hydrolysis gives \( CH_3CHOHCH_3 \), which is propan-2-ol.

**Conclusion:** Reaction II also yields propan-2-ol.

### Step 3: Analyze Reaction III
**Reaction III:** \( CH_2O \overset{C_2H_5MgI}{\rightarrow} \)

1. The formaldehyde \( CH_2O \) reacts with the Grignard reagent \( C_2H_5MgI \).
2. The ethyl group from the Grignard reagent attacks the carbonyl carbon, leading to the formation of a secondary alcohol.
3. The product formed is \( CH_3CH(OH)CH_2 \), which is propan-1-ol, not propan-2-ol.

**Conclusion:** Reaction III does not yield propan-2-ol.

### Step 4: Analyze Reaction IV
**Reaction IV:** \( CH_2=CH-CH_3 \overset{KMnO_4}{\rightarrow} \)

1. The alkene \( CH_2=CH-CH_3 \) is treated with neutral KMnO4, which is a mild oxidizing agent.
2. This reaction leads to syn-dihydroxylation, forming a vicinal diol.
3. The products are formic acid and acetic acid, not propan-2-ol.

**Conclusion:** Reaction IV does not yield propan-2-ol.

### Final Conclusion
The reactions that yield propan-2-ol are:
- Reaction I
- Reaction II

Thus, the correct answer is **(a) I and II**.

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