Chemistry · May / June 2021 · Paper 11 · Question 4

J is an aqueous solution. On addition of aqueous sodium hydroxide to J a green precipitate is formed. The resulting mixture is heated and no gas is formed. Aluminium foil is added to the warmed mixture. A gas is formed that turns damp red litmus paper blue. Which ions could be present in J?

1. AFe3+ and NH4+
2. BFe3+ and NO3–
3. CFe2+ and NH4+
4. DFe2+ and NO3–

As printed in the paper