Question

(a) What is an acid-base indicator? Name the three common indicators used in chemistry laboratory.

(b) Name an acid-base indicator extracted from lichen.

(c) What colour does the methyl orange turn to when put in an acidic solution ?

Answer 1

a) Acid-base indicators are substances that determines whether a solution is an acid or a base primarily based on change in their characteristic colour or odour.

The three common indicators are:-
i. Litmus paper
ii. Methyl orange
iii. Phenolphthalein

b)Acid base indicator extracted from lichen is Litmus which further processed to make litmus paper.

c) Methyl orange changes its colour from orange to red when added to an acidic solution.