AQA A-Level Chemistry Ion Tests

Chemistry Ion tests

Test for Ammonium ion

Test for Ammonium ion

When NaOH is added and gently heated, ammonia gas which turns damp red litmus into blue is released

Test for hydroxide ions

Red litmus paper turns blue

Test for carbonate ions

Add dilute HCl. Fizzing is observed as carbon dioxide is released. Limewater turns cloudy.

Test for Sulphate

HCl followed by Barium Chloride.
White precipitate formed.

Test for Chloride ions in solution

Nitric acid followed by Silver Nitrate.
White precipitate formed.

Test for Chloride ions in solid

Add concentrated Sulphuric Acid.
Produces misty fumes of HCl.

Test for Fluoride ions in solid

Add concentrated Sulphuric Acid.
Produces misty fumes of HF.

Test for Bromide ions in solution

Nitric acid followed by Silver Nitrate.
Cream precipitate formed.

Test for Bromide ions in solid

Add concentrated Sulphuric Acid.
Produces orange fumes of Br₂, and choking fumes of SO₂. Also Misty Fumes of HBr.

Test for Iodide ions in solution

Nitric acid followed by Silver Nitrate.
Yellow precipitate formed.

Test for Iodide ions in solid

Add concentrated Sulphuric Acid.
Production of misty fumes of HI, rotten egg smell (H2S), black solid iodine.

Strontium flame test

red

Barium flame test

pale green

Calcium flame test

Brick red

Test for Alkene

Shake with bromine water.
Orange colour is decolourised.

Test for aldehydes and ketones

Add Tollen's reagent.
Silver mirror formed. Not formed with ketones

Test for Carboxylic Acid

Add aqueous sodium carbonate
Effervescence of Carbon Dioxide is produced

Test for primary and secondary alcohols

Acidified Potassium Dichromate.
Colour change orange to green.

Test for Haloalkane

Warm with silver nitrate.
Precipitate formed.

Test for Acyl Chloride

Add silver nitrate.
Vigorous reaction, steamy fumes of HCl, rapid production of white precipitate.