Aqueous sodium hydroxide is added to a solution of a salt. A blue precipitate is formed which does not dissolve in excess. Aluminium foil is added to the mixture and the mixture is warmed. A gas is produced that turns damp red litmus paper blue. <br/>What is the name of the salt?

• Aammonium nitrate
• Bammonium sulphate
• Ccopper(II) nitrate
• Dcopper(II) sulphate

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