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2017 O Level Chem P1 Q20 — Ammonia / Properties of Ammonia Solution

Ammonia / Properties of Ammonia 2017 O Level Pure Chemistry · Paper 1 · Q20

Question

Which statement about ammonia is correct?

AIt decomposes on heating to a high temperature to form nitrogen and hydrogen.
BIt dissolves in water to form an acidic solution.
CIt is formed when ammonium salts are heated with sulfuric acid.
DIt reacts with alkalis to form salts.

Correct answer: A

Video Solution

Explanation

Answer: A. Ammonia decomposes when heated to a high temperature into nitrogen and hydrogen: \(2\text{NH}_3 \rightarrow \text{N}_2 + 3\text{H}_2\).

B is wrong (ammonia dissolves to give an alkaline solution). C is wrong (ammonia is released when ammonium salts are heated with an alkali, not an acid). D is wrong (ammonia is a base, so it reacts with acids, not alkalis, to form salts).

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