Chemistry Question from JEE Main 2023 · 8 April, Shift 1

The titration curve of a weak acid against a strong base, using phenolphthalein as the indicator, is shown below.

Given: $K_{\text{phenolphthalein}} = 4 \times 10^{-10}$ and $\log 2 = 0.3$.

The number of the following statements which is/are correct about phenolphthalein is _____.

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

(B) It begins to change colour at $\text{pH} = 8.4$.

(C) It is a weak organic base.

(D) It is colourless in acidic medium.