AIIMS 2017
- Exam
- AIIMS
- Year
- 2017
- Subject
- Chemistry
- Chapter
- Chemical Bonding and Molecular Structure
AIIMS 2017 · Chemistry · Chemical Bonding and Molecular Structure
Assertion: The second dissociation constant of fumaric acid is...
Assertion: The second dissociation constant of fumaric acid is greater than maleic acid.
Reason : Higher the dissociation constant of acid, more is the acidic character.
Options
- AIf both assertion and reason are true and reason is the correct explanation of assertion.
- BIf both assertion and reason are true but reason is not the correct explanation of assertion.
- CIf assertion is true but reason is false.
- DIf both assertion and reason are false.
Correct answer
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
Step-by-step solution
Both fumaric and maleic acids have two ionisable ions i.e., protons. The maleate monoanion shows intramolecular -bonding, whereas fumarate monoanion shows intermolecular -bonding. Thus, fumarate monoanion requires more energy to give fumarate dianion. Hence, second dissociation of fumaric acid is more than that of maleic acid.