JEE Main 2022ChemistryRedox ReactionsMediumMCQ

JEE Main 2022 — Redox Reactions Question with Solution

JEE Main 2022 (26 Jul Shift 2)

Question

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

Choose an option

Show full solutionCorrect option: C
Correct answer
CA is true but R is false

Step-by-step explanation

Phenolphthalein, (C20H14O4), an organic compound of the phthalein family that is widely employed as an acid-base indicator. As an indicator of a solution’s pH, phenolphthalein is colourless below pH 8.5 and attains a pink to deep red hue above pH 9.0.

Phenolphthalein dissociate in basic medium

HPhaqcolourless⇌H++Ph-Pink

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About this question

This is a previous-year question from JEE Main 2022, covering the Redox Reactions chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.