Acids, Bases and Salts (IGCSE Edexcel Chemistry)

Colour of litmus in acid

red

colour of litmus in alkali

blue

Phenolphthalein in acid

Colourless

Phenolphthalein in alkali

pink

Phenolphthalein in water

colourless

Methyl orange in acid

red

Methyl orange in alkali

yellow

Methyl orange in water

orange

Universal indicator in strong acid

red

Universal indicator in weak acid

orange/yellow

Universal indicator in weak base

blue

Universal indicator in strong alkali

purple

All acids have this ion

hydrogen ion / proton

All alkalis have this ion

hydroxide ion

Acids are also known as

proton donors

Bases are also known as

proton acceptors

hydrochloric acid + sodium hydroxide

sodium chloride + water

sulphuric acid + magnesium

Magnesium sulphate + hydrogen

nitric acid + sodium carbonate

sodium nitrate + water + carbon dioxide

magnesium oxide + hydrochloric acid

magnesium chloride + water

sodium carbonate + sulphuric acid

sodium sulphate + water + carbon dioxide

All metal oxides are....

.... bases

All group one, ammonium and ...... salts are soluble

nitrates

All chlorides are soluble except

lead and silver chloride

All sulphates are soluble except

lead, calcium and barium

All carbonates and hydroxides are insoluble except

group 1 and ammonium carbonates

Group 1 salts are usually made in a process called

titration

Insoluble salts are made in a process called

precipitation reaction

ammonia + hydrochloric acid

ammonium chloride

ammonium hydroxide + sulphuric acid

ammonium sulphate + water