A sample of X is warmed with aqueous sodium hydroxide and small pieces of aluminium. A gas is given off that turns red litmus paper blue. Aqueous sodium hydroxide solution is then added to a second sample of X. A pale green precipitate is seen. What is X?
- Aammonium nitrate
- Bchromium(II) chloride
- Ciron(II) nitrate
- Diron(II) sulfate