Question

Explain why there is an uncertainty in pH values that are measured using universal indicator.

Please help!!

Answer 1

Answer:The chemical properties of many solutions enable them to be divided into three categories - acidic, alkaline and neutral solutions.

The pH scale is used to measure acidity and alkalinity:

solutions with a pH less than 7 are acidic

solutions with a pH of 7 are neutral

solutions with a pH greater than 7 are alkaline

If universal indicator is added to a solution it changes to a colour that shows the pH of the solution. Universal indicator is a mixture of a variety of other indicators and can be used to measure the approximate pH of a solution. A more accurate value can be obtained using a pH probe.

A coloured pH scale, ranging from dark red at pH 0, orange at pH 3, green at pH 7, blue at pH 10 to dark purple at pH 14.

pH scale and universal indicator colours

Answer 2

The chemical properties of many solutions enable them to be divided into three categories - acidic, alkaline and neutral solutions.

The pH scale is used to measure acidity and alkalinity:

solutions with a pH less than 7 are acidic

solutions with a pH of 7 are neutral

solutions with a pH greater than 7 are alkaline

If universal indicator is added to a solution it changes to a colour that shows the pH of the solution. Universal indicator is a mixture of a variety of other indicators and can be used to measure the approximate pH of a solution. A more accurate value can be obtained using a pH probe.

A coloured pH scale, ranging from dark red at pH 0, orange at pH 3, green at pH 7, blue at pH 10 to dark purple at pH 14.

pH scale and universal indicator colours