Question

The titration curve of weak acid vs. strong base with phenolphthalein as indictor is shown below. The K_{phenolphthalein} = 4 × 10^-10 . 

Given: log2 = 0.3

The number of following statements which is/are correct about phenolphthalein is______ 

A. It can be used as an indicator for the titration of weak acid with weak base.

B. It begins to change colour at pH = 8.4 

C. It is a weak organic base

D. It is colourless in acidic medium

Answer 1

Correct answer is 2

(D) In acidic medium, phenolphthalein is in unionized form and is colourless.