Acids are compounds which dissolve in water giving hydrogen ions. Sulphuric acid is one example. It is a strong acid, which can be neutralized by alkalis to form salts called sulphates.
Many metals react with acids to give a gas called hydrogen. Acids also react with carbonates to give carbon dioxide.
Solutions of acids are poor conductors of electricity. They also affect indicators. For example, phenolphthalein turns colourless in acids, while litmus turns red.
Alkalis are compounds that dissolve in water giving hydroxide ions. They have a pH number greater than 7.
