When excess aqueous ammonia reacts with ethyl bromide () under reflux, which of the following is the major product?
Answer
Ethylamine ()
The correct answer is Ethylamine () — Therefore, the major product isolated is ethylamine.
Step-by-step solution
- The reaction proceeds via an mechanism because the primary alkyl halide is unhindered.
- Excess ammonia () acts as the nucleophile and displaces bromide to give ethylamine.
- Although secondary and tertiary amines can form by further substitution, the large excess of suppresses these side reactions.
- Therefore, the major product isolated is ethylamine.
Common mistake: Choosing diethylamine as the major product, forgetting that excess favours formation of the primary amine.
Concept tested: Nucleophilic substitution of alkyl halides with ammonia
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