Precipitation reactions

Precipitation

The process of obtaining an insoluble salt from a solution.

What can precipitation reactions be used for?

To identify different dissolved ions and remove soluble metal ions from solutions.

What is the result of mixing two solutions in a precipitation reaction?

A solution of soluble products and an insoluble precipitate in the filter funnel.

Potassium ion test result

Lilac flame.

Lithium ion test result

Crimson flame.

Calcium ion test result

Orange/red flame.

Copper ion test result

Green flame.

Sodium ion test result

Yellow flame.

Sulfate test reaction equation

HCl + BaCl2 → white precipitate.

Carbonate test reaction

HCl → CO2 gas produced.

Chloride test reaction equation

HNO3 + AgNO3 → white precipitate.

Bromide test reaction equation

HNO3 + AgNO3 → cream precipitate.

Iodide test reaction equation

HNO3 + AgNO3 → yellow precipitate.

Flame tests

Identifies metal ions by the colours they produce when heated.

Carbonate test

Tests for carbon dioxide by turning limewater cloudy.

Sulfates test outcome

Barium chloride forms an insoluble white precipitate when sulfates are present.

Halides test outcome

Halides produce silver coloured halide precipitates when reacted with silver nitrate solution.