Acids And Bases

Acids taste sour feel rough are corrosive (attacks other substances or materials) Examples are lemon juice, vinegar, fruit juice, pool acid Bases taste bitter feel slipper on skin dangerous to taste or feel because they are corrosive Examples are soap, bleach, washing powder Neutrals They are neither acids nor bases Examples are water, salt, sugar, cooking oil

An indicator is a substance which changes colours when in contact with an acid or base. A litmus paper is an indicator to test whether the substance is an acid, base or neutral. If an acid touches a red litmus paper it stays red, but when it touches a blue litmus paper it turns red. When a neutral touches a red litmus paper it stays the same colour as the same when it touches a blue litmus paper. When a base touches a red litmus paper it turns blue. When it touches a blue litmus paper it stays blue. This is how we can indicate whether the substance is an acid, base or neutral.