Identification of Cations
| Add a few drops of NaOH | Add excess NaOH | Add Ammonia to fresh sample | |
| +
NH4 |
No precipitate formed | When warm = litmus blue | – |
| Cu2+ | Blue precipitate formed | – | – |
| Fe2+ | Green precipitate formed | – | – |
| Fe3+ | Orange/Brown precipitate | – | – |
| Al3+ | White precipitate | Precipitate dissolves | Insoluble white precipitate |
| Ca2+ | White precipitate | Precipitate remains | – |
| Zn2+ | White precipitate | Precipitate dissolves | Soluble white precipitate |