Testing for ions and cations

Lithium

Do the flame test, the outcome will be red

Sodium

Do the flame test, the outcome will be yellow

Potassium

Do the flame test, the outcome will be lilac (NOT PURPLE)

Calcium

Do the flame test, the outcome will be orange-red (brick red)

Copper

Do the flame test, the outcome will be blue-green (apple green)

How to carry out a flame test?

Dip a loop of an unreactive metal wire (such as nichrome or platinum) into dilute acid

Hold it to the blue flame of a Bunsen burner until there is no change

Dip the loop into the solid sample and hold it to a blue Bunsen burner flame

Ammonia

Add Sodium Hydroxide to the solution, then warm it, hold red damp litmus paper at the mouth of the test tube, if ammonium is present it’ll turn from red to blue

Carbon dioxide

Turns limewater cloudy

Chlorine gas

Put litmus paper to a mouth of a test tube with chlorine gas. The damp litmus paper will turn from blue to red then to white. It’ll be bleached

Hydrogen

Burns with a squeaky pop

Oxygen

Relights a glowing splint

How to carry out a cation test?

Add a small amount of sodium hydroxide to the metal, since the metal is a solid it will form a precipitate of colour

Copper (cation test)

Light blue percipitate

Iron 2+

Green precipitate

Iron 3+

Brown precipitate

Carbonate ions test

Add a dilute acid (HCl)

Bubble the gas produced through lime water, if the limewater turns cloudy carbonate ions are present

Halide ions test

Add silver nitrate and see what precipitate will be formed

Chloride

White precipitate

Bromide

Cream precipitate

Iodide

Yellow precipitate

Sulfate ions test

Add some hydrochloric acid

Then add some barium chloride solution

A white precipitate of barium sulfate id formed if sulfate is present

Test for water

Anhydrous copper sulfate turns from white to blue when water is added

Pure water will also turn to ice at 0 degrees Celsius, and turns to steam at 100 degrees Celsius.