A mixture of dyes is called universal indicator. This is more useful than litmus as it can be used to measure how strong an acid or an alkali is using the pHscale. A pH of 7 is neutral (like for example water); a pH of 1 or 2 is a strong acid (for example sulfuric acid); weak acids like vinegar have a pH of 3 to 6. Weak alkalis (like soap) have pH values of 8 to 10 and a strong alkali like sodium hydroxide will have a pH of 13 or 14.
1
5
9
14
Ethanoic acid
Hydrochloric acid
Nitric acid
Sulfuric acid
An orange
Bleach
Distilled water
Washing powder
1
5
7
14
Baking powder
Coca cola
Distilled water
Vinegar
Green
Orange
Purple
Red
Able to turn blue litmus paper red
Corrosive and/or caustic
Sour
Sweet
Green
Orange
Purple
Red
Green
Orange
Purple
Red
1
5
7
14