Cation Test: Sodium Hydroxide Test Flashcards
Hydroxide precipitate test for Aluminium, Al3+
White
Hydroxide precipitate test for Calcium, Ca2+
White
Hydroxide precipitate test for Magnesium, Mg2+
White
Hydroxide precipitate test for Copper(II), Cu2+
Blue
Hydroxide precipitate test for Iron(II), Fe2+
Green
Hydroxide precipitate test for Iron(III), Fe3+
Orange-brown
Hydroxide precipitate test for Zinc, Zn2+
White
How to differentiate between aluminium, calcium, magnesium, and zinc hydroxide?
Add an excess of sodium hydroxide. Aluminium and zinc hydroxide will dissolve to form a colourless solution. Magnesium and calcium will not.
In excess sodium hydroxide, the white precipitate dissolved and became colourless.
Either aluminium or zinc.
White precipitate was formed in sodium hydroxide.
Either aluminium, zinc, magnesium, or calcium.
In excess sodium hydroxide, the white precipitate did not dissolve, it remained unchanged.
Either magnesium or calcium.
Blue precipitate was formed when sodium hydroxide was added.
Copper (II), Cu2+
Green Precipitate was formed when sodium hydroxide was added.
Iron (II), Fe2+
Orange-brown precipitate was formed when sodium hydroxide was added.
Iron (III), Fe3+
How to do the sodium hydroxide precipitate test?
You add a few drops of sodium hydroxide solution to a solution containing metal ions, a precipitate will be formed (the metal hydroxide) if metal ions are present.
