A fertiliser in the solid state contains ammonium sulfate. A portion of the fertiliser is mixed with water by shaking. To demonstrate the presence of ammonium ions in the solution, .....1..... is added and the gas given off is tested using damp .....2..... litmus paper. Which words complete gaps 1 and 2?
- Aaqueous sodium hydroxide, blue
- Baqueous sodium hydroxide, red
- Cdilute hydrochloric acid, blue
- Ddilute hydrochloric acid, red