(i) An indicator is a substance which shows by means of a colour change whether a substance is an acid or an alkali.

(ii) The pH scale is a measure of how acidic or alkaline a substance is. It goes from 0-14 where 7 is neutral; less than 7 is acidic and greater than 7 is alkaline. The stronger the acid the nearer the pH is to 0 and the stronger the alkaline the nearer the pH is to 14.

Title; To measure the pH of a solution

Apparatus: Universal indicator, dropper, universal indicator chart

Method:

1. Place a drop of solution on to the universal indicator paper.
2. Compare the colour of the paper with the indicator chart.

Result: The nearest colour match on the chart is the pH of the solution.

Dilute sulphuric acid pH = 3

Dilute sodium hydroxide pH = 11

A neutralisation reaction (because the pH of the mixture will be neutral)