Which one/ones of the following reactions will yield 2-propanol ?
(I) `CH_2=CH-CH_3+H_2Ooverset(H^(+))to`
(II) `CH_3-CHOoverset((i)CH_3Mgl)underset((ii)H_2O)to`
(III) `CH_2overset((i)C_2H_5MgI)underset((ii)H_2O)to`
(IV) `CH_2=CH-CH_3overset("Neutral " KMnO_4)to`

Options

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

Answer

To determine which reactions yield 2-propanol, we will analyze each reaction step by step.

### Step 1: Analyze Reaction I
**Reaction I:**
\[ \text{CH}_2=CH-CH_3 + H_2O \overset{H^+}{\rightarrow} \]

- This is an acid-catalyzed hydration of propene (CH₂=CH-CH₃).
- According to Markovnikov's rule, the hydrogen atom from water will add to the carbon with more hydrogen atoms (the terminal carbon), and the hydroxyl group (OH) will add to the carbon with fewer hydrogen atoms.
- The product formed will be:
\[ \text{CH}_3-CH(OH)-CH_3 \]
- This is 2-propanol.

### Step 2: Analyze Reaction II
**Reaction II:**
\[ \text{CH}_3-CHO \overset{(i) \text{CH}_3MgI}{\rightarrow} \overset{(ii) H_2O}{\rightarrow} \]

- Here, acetaldehyde (CH₃CHO) reacts with a Grignard reagent (CH₃MgI).
- The Grignard reagent adds to the carbonyl carbon of acetaldehyde, forming a tertiary alcohol.
- The product formed after the addition of water will be:
\[ \text{CH}_3-CH(OH)-CH_3 \]
- This is also 2-propanol.

### Step 3: Analyze Reaction III
**Reaction III:**
\[ \text{CH}_2 + (i) \text{C}_2H_5MgI \overset{(ii) H_2O}{\rightarrow} \]

- In this reaction, the Grignard reagent (C₂H₅MgI) adds to a carbon atom (not specified, assuming it is a carbonyl compound).
- The reaction does not specify the starting material clearly, but typically, if it were to add to a carbonyl compound, it would not yield 2-propanol.
- The product formed here would not be 2-propanol.

### Step 4: Analyze Reaction IV
**Reaction IV:**
\[ \text{CH}_2=CH-CH_3 \overset{\text{Neutral } KMnO_4}{\rightarrow} \]

- This is a reaction with neutral potassium permanganate (KMnO₄), which typically oxidizes alkenes.
- The product formed from this reaction would be:
\[ \text{CH}_3-CHOH-CHOH-CH_3 \]
- This is not 2-propanol, but rather a diol.

### Conclusion
From the analysis:
- **Reactions I and II** yield 2-propanol.
- **Reactions III and IV** do not yield 2-propanol.

### Final Answer
The reactions that yield 2-propanol are:
- **(I) and (II)**.

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