Question

Indicator - Thymol Blue, Phenol Red, Alizarin Yellow

Colour Observed - Blue, Red, Yellow


A solution of unknown [H3O+] is mixed several indicators and the results are shown: What is the approximate pH range of the solution?

Answer 1

Thymol Blue has blue color at the pH range 9.6 - 14.0

Phenol Red has red colour at the pH range 8.0 - 14.0

Alizarin Yellow has yellow colour at the pH range 1.0 - 10.0

The approximate pH range of the solution is 9.6 - 10.0