Compound A and C in the following reaction are …………………………. `CH_(3)CHO overset((i)CH_3MgBr)underset((ii)H_2O)to A overset(H_2SO_4)underset(Delta)toBoverset("Hydroboration")underset("Oxidation")toC`

Options

A. identical
B. position isomer
C. functional isomer
D. optical isomer

Answer

To solve the problem, we need to analyze the reactions step by step and identify the compounds A and C, then determine the relationship between them.

### Step 1: Identify Compound A
The starting compound is CH₃CHO (acetaldehyde). When it reacts with CH₃MgBr (a Grignard reagent), it undergoes nucleophilic addition. The nucleophile (CH₃⁻) attacks the electrophilic carbon of the carbonyl group (C=O), leading to the formation of an alkoxide intermediate.

**Reaction:**
\[ \text{CH}_3CHO + \text{CH}_3MgBr \rightarrow \text{CH}_3CH(OH)CH_3 \]

After hydrolysis (addition of water), the alkoxide is converted to an alcohol. Thus, compound A is:
\[ \text{A} = \text{CH}_3CH(OH)CH_3 \] (2-propanol)

### Step 2: Identify Compound B
Next, we treat compound A with H₂SO₄ and heat it. This leads to dehydration, where water is removed from the alcohol, forming a carbocation. The reaction can be summarized as follows:

**Reaction:**
\[ \text{CH}_3CH(OH)CH_3 \xrightarrow{H_2SO_4, \Delta} \text{CH}_3C^+(CH_3) \]

The carbocation can lose a proton (H⁺) to form an alkene:
\[ \text{B} = \text{CH}_3C(CH_3)=CH_2 \] (propene)

### Step 3: Identify Compound C
The final step involves hydroboration-oxidation of compound B. Hydroboration involves the addition of BH₃ followed by oxidation with H₂O₂ in basic medium, leading to the formation of an alcohol.

**Reaction:**
\[ \text{CH}_3C(CH_3)=CH_2 \xrightarrow{\text{BH}_3/\text{H}_2\text{O}_2} \text{CH}_3CH₂CH₂OH \]

Thus, compound C is:
\[ \text{C} = \text{CH}_3CH_2CH_2OH \] (1-propanol)

### Step 4: Determine the Relationship between A and C
Now we need to identify the relationship between compounds A and C. Both compounds A and C have the same molecular formula (C₃H₈O), but they differ in the position of the hydroxyl (OH) group.

- **Compound A (2-propanol)** has the OH group on the second carbon.
- **Compound C (1-propanol)** has the OH group on the first carbon.

Since the only difference between A and C is the position of the functional group (the hydroxyl group), they are classified as **positional isomers**.

### Final Answer
Compound A and C in the reaction are **positional isomers**.

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