JEE Main 2022 · 26 Jul · Shift 2 · Chemistry Q80

ChemistrySingle correct+4 / -1Question 80 of 90

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A: Phenolphthalein is a pH dependent indicator, remains colourless in acidic solution and gives pink colour in basic medium.

Reason R: Phenolphthalein is a weak acid. It doesn't dissociate in basic medium.

In the light of the above statements, choose the most appropriate answer from the options given below.

Both A and R are true and R is the correct explanation of A.

Both A and R are true but R is NOT the correct explanation of A.

A is true but R is false.

A is false but R is true.

Answer and worked solution

Official answer: C

Assertion. Phenolphthalein is colourless in acid and pink in base. True.

Reason. It is a weak acid that does ionise in basic medium, and the ion is pink. False.

(C)

Topics:Indicators and titrations

JEE Main 2022 · 26 Jul · Shift 2, Chemistry question 80