NEETChemistryRedox Reactions
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
Options
- ABoth A and R are true and R is the correct explanation of A
- BBoth A and R are true but R is NOT the correct explanation of A .
- CA is true but R is false
- DA is false but R is true
Correct answer
C. A is true but R is false
Step-by-step solution
Phenolphthalein, ( C 20 H 14 O 4 ) , 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 HPh aq colourless ⇌ H + + Ph - Pink