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

Explanation

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

### Step 1: Analyze Reaction I
**Reaction I:**
\[ \text{CH}_2=\text{CH}-\text{CH}_3 + \text{H}_2\text{O} \overset{H^+}{\rightarrow} \]

1. This is an addition reaction of water (hydration) to propene (CH₂=CH-CH₃).
2. According to Markovnikov's rule, the OH group from water will add to the carbon with fewer hydrogen atoms.
3. The double bond is between the first and second carbon atoms. The first carbon has two hydrogens, and the second carbon has one hydrogen.
4. Therefore, OH will attach to the second carbon, and H will attach to the first carbon.
5. The resulting structure is:
\[ \text{CH}_3-\text{C(OH)}-\text{CH}_3 \]
6. This compound is propan-2-ol.

**Conclusion for Reaction I:** This reaction yields propan-2-ol.

### Step 2: Analyze Reaction II
**Reaction II:**
\[ \text{CH}_3-\text{CHO} \overset{\text{CH}_3\text{MgI}/\text{H}_2\text{O}}{\rightarrow} \]

1. Here, we have acetaldehyde (CH₃CHO) reacting with a Grignard reagent (CH₃MgI).
2. The Grignard reagent will attack the carbonyl carbon of the aldehyde.
3. The carbonyl oxygen will become negatively charged (alkoxide).
4. Upon hydrolysis, the alkoxide will be converted to an alcohol.
5. The product will be:
\[ \text{CH}_3-\text{C(OH)}-\text{CH}_3 \]
6. This is also propan-2-ol.

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

### Step 3: Analyze Reaction III
**Reaction III:**
\[ \text{CH}_2\text{O} \overset{H_2\text{O}}{\underset{\text{C}_2\text{H}_5\text{MgI}}{\rightarrow}} \]

1. Here, formaldehyde (HCHO) reacts with ethyl magnesium iodide (C₂H₅MgI).
2. The ethyl group from the Grignard reagent will attack the carbonyl carbon of formaldehyde.
3. The resulting product after hydrolysis will be:
\[ \text{CH}_2\text{(OH)}-\text{CH}_2\text{CH}_3 \]
4. This compound is propan-1-ol, not propan-2-ol.

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

### Step 4: Analyze Reaction IV
**Reaction IV:**
\[ \text{CH}_2=\text{CH}-\text{CH}_3 \overset{\text{Neutral KMnO}_4}{\rightarrow} \]

1. This reaction involves the oxidation of propene using neutral potassium permanganate.
2. The reaction will lead to syn-dihydroxylation, resulting in the addition of OH groups across the double bond.
3. The product will be:
\[ \text{CH}_2(\text{OH})-\text{CH}(\text{OH})-\text{CH}_3 \]
4. This compound is not propan-2-ol; it is a diol.

**Conclusion for Reaction IV:** This reaction 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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