The compound (A) in the following reaction sequence is:
(A) `overset(PCl_(5))(rarr) " (B) " overset("Alc KOH")(rarr) " ( C) " overset(H_(2)// Ni )(rarr)`
Propane :

Options

A. Chloroethane
B. Ethanol
C. 1,2-Dichloroethane
D. None of the above

Answer

To determine the compound (A) in the given reaction sequence that ultimately leads to propane (C), we will analyze the reactions step by step.

### Step 1: Identify the reaction with PCl5
The first reaction involves the compound (A) reacting with phosphorus pentachloride (PCl5). PCl5 is known to convert alcohols into alkyl chlorides by replacing the hydroxyl (OH) group with a chlorine (Cl) atom.

### Step 2: Determine the structure of (A)
Since we want to end up with propane (C) after a series of reactions, we can deduce that (A) should be an alcohol that can be converted to an alkyl chloride. The simplest alcohol that can lead to propane is **propan-1-ol (CH3CH2CH2OH)**. When propan-1-ol reacts with PCl5, it will convert to **1-chloropropane (B)**.

### Step 3: Reaction with alcoholic KOH
Next, the compound (B), which is 1-chloropropane, reacts with alcoholic KOH. Alcoholic KOH acts as a base and promotes elimination reactions (dehydrohalogenation). In this case, it will remove a hydrogen atom and a chlorine atom from the 1-chloropropane, resulting in the formation of **propene (C)**.

### Step 4: Catalytic hydrogenation
Finally, propene (C) undergoes catalytic hydrogenation in the presence of hydrogen gas and a nickel catalyst. This reaction adds hydrogen across the double bond of propene, converting it to **propane**.

### Conclusion
Based on the above steps, the compound (A) that leads to propane through the described reaction sequence is **propan-1-ol (CH3CH2CH2OH)**.

### Final Answer:
**Compound (A) is propan-1-ol (CH3CH2CH2OH).**

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