Sodium hydroxide (NaOH) test results
Add 2OH- or 3OH- (dependant on ion)
E.g. Ca2+(aq) + 2OH- → Ca(OH)2(s)
Ca2+ → Ca(OH)2(s) → white precipitate
Cu2+ → Cu(OH)2(s) → blue precipitate
Fe2+ → Fe(OH)2(s) → green precipitate
Fe3+ → Fe(OH)3(s) → brown precipitate
Al3+ → Al(OH)3(s) → white precipitate, dissolves in excess NaOH
Mg2+ → Mg(OH)2(s) → white precipitate, does not dissolve in excess NaOH
