Question

In the titration of strong acid and weak base, indicator used is 

(a) methyl orange

(b) phenolphthalein

(c) thymolphthalein

(d) none of these

Answer 1

Correct option is (a) methyl orange

At the equivalence point the pH of the solution will be on the acidic side due to salt hydrolysis. A slight excess of the acid lowers the pH to about 3.5 when methyl orange gives red colour.