`CH_3OHoverset(PI_3)rarr(A)overset(KCN)rarr(B)overset("Hydrolysis")rarr(C).`
The compound (C) is :

Options

A. `CH_3OH`
B. `HCOOH`
C. `CH_3CHO`
D. `CH_3COOH`

Explanation

To solve the problem step by step, we will analyze the reactions sequentially.

### Step 1: Formation of Compound A
- We start with **methanol (CH₃OH)** and react it with **phosphorus triiodide (PI₃)**.
- The reaction of an alcohol with PI₃ converts the alcohol into the corresponding alkyl iodide.
- Therefore, when methanol reacts with PI₃, we get **methyl iodide (CH₃I)**.

**Compound A:** CH₃I

### Step 2: Formation of Compound B
- Next, we take **methyl iodide (CH₃I)** and react it with **potassium cyanide (KCN)**.
- KCN dissociates into K⁺ and CN⁻ ions in solution. The CN⁻ ion acts as a nucleophile.
- In an SN2 reaction, the nucleophile (CN⁻) attacks the electrophilic carbon in methyl iodide, displacing the iodide ion (I⁻), which is a good leaving group.
- This results in the formation of **methyl cyanide (CH₃CN)**.

**Compound B:** CH₃CN

### Step 3: Formation of Compound C
- Finally, we take **methyl cyanide (CH₃CN)** and subject it to **hydrolysis**.
- Hydrolysis of nitriles (like methyl cyanide) involves the addition of water, which converts the nitrile into the corresponding carboxylic acid.
- Therefore, hydrolysis of CH₃CN yields **acetic acid (CH₃COOH)**.

**Compound C:** CH₃COOH

### Final Answer
The compound (C) is **acetic acid (CH₃COOH)**.

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