Question

What is the effect of sulphuric acid on the following?

(a) Red litmus
(b) Blue litmus
(c) Phenolphthalein

Answer 1

Acids turn blue litmus paper to red. Sulphuric acid belongs to the category of acids. Let us see the effect of sulphuric acid on
(a) Red litmus: If the litmus paper is red, sulphuric acid will not have any effect on the paper. The litmus paper will remain red.
(b) Blue litmus: The blue litmus paper changes to red in the presence of sulphuric acid.
(c) Phenolphthalein: Phenolphthalein is an indicator solution which turns colourless in the presence of acids. Therefore, in the presence of sulphuric acid, phenolphthalein turns colourless.