At 0 °C, glycine (NH₂CH₂COOH) is treated with excess nitrous acid (HNO₂). What gas is evolved?
Answer
Nitrogen (N₂)
The correct answer is Nitrogen (N₂) — The diazonium decomposes, releasing nitrogen gas (N₂) and converting the amino group into a carboxyl group.
Step-by-step solution
- Recognise that glycine contains a primary amino group.
- Nitrous acid reacts with primary amines to form a diazonium intermediate.
- The diazonium decomposes, releasing nitrogen gas (N₂) and converting the amino group into a carboxyl group.
Common mistake: Assuming ammonia or water is released instead of N₂
Concept tested: Primary amine oxidation to N₂ gas
Published · How this solution was prepared and checked
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