Identify A,B and C in the following reaction sequence compounds : .
`CH_(3) CH_(2) OH overset(SoCl_(2)) to A underset("dryacetone")overset(+KI) to B overset(AqCN)to C`

Options

A. `CH_(3)CH_(2)CI,CH_(3)CH_(3),CH_(3)CH_(2)NC`
B. `CH_(3)CH_(2)Cl, CH_(3)CH_(3),CH_(3)CH_(2)CN`
C. `CH_(3)CH_(2)Cl, CH_(2)CH_(2)I, CH_(3)CH_(3)NC`
D. `CH_(3)CH_(2)Cl, CH_(3)CH_(3)l, CH_(3)CH_(2)CN`

Explanation

To identify the compounds A, B, and C in the given reaction sequence, we will analyze each step of the reaction.

### Step 1: Identify Compound A
The starting compound is **CH₃CH₂OH** (ethanol). When ethanol reacts with **SOCl₂** (thionyl chloride), it undergoes a conversion to form an alkyl chloride. The reaction can be represented as follows:

\[ \text{CH}_3\text{CH}_2\text{OH} + \text{SOCl}_2 \rightarrow \text{CH}_3\text{CH}_2\text{Cl} + \text{SO}_2 + \text{HCl} \]

Thus, compound A is **CH₃CH₂Cl** (ethyl chloride).

### Step 2: Identify Compound B
Next, compound A (ethyl chloride) is treated with **dry acetone** and **KI** (potassium iodide). In this reaction, ethyl chloride undergoes an **SN2 reaction** with iodide ion from KI, resulting in the formation of an alkyl iodide. The reaction can be represented as follows:

\[ \text{CH}_3\text{CH}_2\text{Cl} + \text{KI} \rightarrow \text{CH}_3\text{CH}_2\text{I} + \text{KCl} \]

Thus, compound B is **CH₃CH₂I** (ethyl iodide).

### Step 3: Identify Compound C
Finally, compound B (ethyl iodide) is treated with **aqueous cyanide (AqCN)**. In this reaction, ethyl iodide reacts with cyanide ion (CN⁻) to form a nitrile through an SN2 mechanism. The reaction can be represented as follows:

\[ \text{CH}_3\text{CH}_2\text{I} + \text{CN}^- \rightarrow \text{CH}_3\text{CH}_2\text{CN} + \text{I}^- \]

Thus, compound C is **CH₃CH₂CN** (ethyl cyanide or propionitrile).

### Summary of Compounds
- **A**: CH₃CH₂Cl (ethyl chloride)
- **B**: CH₃CH₂I (ethyl iodide)
- **C**: CH₃CH₂CN (ethyl cyanide)