Copper reacts with 50% nitric acid to give a blue solution A and a brown gas B. If the solution A is diluted and sodium hydroxide solution added cautiously, a gelatinous blue precipitate C is obtained, which if warmed forms a black solid G.

Addition of concentrated ammonia solution to C gives a deep blue solution that contains the ion D. Addition of concentrated hydrochloric acid to C gives a green solution of the ion E, which on dilution with water gives a solution of the ion F.

If the brown gas B is passed into water a mixture of acids H and I is formed in a disproportionation reaction.

Identify A - I, giving equations for and explaining each reaction as far as possible.

© JRG Beavon 1999

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