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 reaction sequence that leads to propane (C3H8), we need to analyze each step of the reaction sequence carefully.

### Step 1: Understanding the Reaction Sequence
The reaction sequence is as follows:
1. (A) reacts with PCl5 to form (B).
2. (B) reacts with alcoholic KOH to form (C).
3. (C) reacts with H2 in the presence of Ni to yield propane.

### Step 2: Analyzing the Final Product (C)
The final product (C) is propane (C3H8). This indicates that (C) must be a compound that can be converted to propane through hydrogenation (addition of H2).

### Step 3: Identifying (B)
Since (B) is formed from (A) by the action of PCl5, (B) is likely a haloalkane (alkyl halide). The presence of PCl5 suggests that (A) must contain hydroxyl (-OH) groups that can be converted to halides.

### Step 4: Identifying (A)
To produce a compound (C) that can be converted to propane, (A) must have a structure that allows for the formation of a haloalkane with three carbon atoms. The options for (A) could be:
- 1-propanol (C3H8O)
- 2-propanol (C3H8O)

Both 1-propanol and 2-propanol can react with PCl5 to form the corresponding alkyl chlorides (1-chloropropane or 2-chloropropane).

### Step 5: Reaction with Alcoholic KOH
When (B) (the haloalkane) is treated with alcoholic KOH, it undergoes elimination to form an alkene (propene, C3H6). This is consistent with the reaction conditions provided.

### Step 6: Hydrogenation to Form Propane
Finally, the alkene (C) can be hydrogenated using H2 and Ni to yield propane.

### Conclusion
Based on the analysis, the compound (A) must be either 1-propanol or 2-propanol. Since the question asks for a specific compound and the options provided in the video were not valid, we conclude that the answer is:

**(A) = 1-propanol or 2-propanol.**