Step 1: Understanding the Concept:
This sequence involves the reduction of an amide to an amine, the conversion of a primary amine to an alcohol, and finally the oxidation of a primary alcohol.
Step 2: Detailed Explanation:
1. Reduction: \(CH_{3}CH_{2}CONH_{2}\) (Propanamide) is reduced by \(LiAlH_{4}\) to form A, which is \(CH_{3}CH_{2}CH_{2}NH_{2}\) (Propan-1-amine).
2. Diazotization and Hydrolysis: Treatment of a primary aliphatic amine with \(HNO_{2}\) followed by water converts the \(-NH_{2}\) group into an \(-OH\) group. Thus, B is \(CH_{3}CH_{2}CH_{2}OH\) (Propan-1-ol).
3. Controlled Oxidation: \(CrO_{3}\) in anhydrous medium is a mild oxidizing agent that converts primary alcohols into aldehydes. Thus, C is \(CH_{3}CH_{2}CHO\) (Propanal).
Step 3: Final Answer:
The final product C is propanal.