All Exams  >   MCAT  >   MCAT Chemical and Physical Foundations  >   All Questions

All questions of Aldehydes, Ketones and Carboxylic Acids (OC) for MCAT Exam

Arrange the following compounds in decreasing order of their acid strength: i) trichloroacetic acid ii) trifluoroacetic acid iii) acetic acid and iv) formic acid
  • a)
    trifluoroacetic acid, trichloroacetic acid, formic acid and acetic acid
  • b)
    formic acid., trifluoroacetic acid, trichloroacetic acid, and acetic acid
  • c)
    trichloroacetic acid, trifluoroacetic acid, acetic acid and formic acid.
  • d)
    trifluoroacetic acid, formic acid acetic acid and Propan – 1 – ol, 4 – methylphenol
Correct answer is option 'A'. Can you explain this answer?

Tanuja Kapoor answered
Acidic strength of carboxylic acid -
–  More acidic than phenols or alcohols.
–  Acidity increase with the presence of a group with  -I effect in the alkyl group.Whereas it decreases with the presence of  +I group.
–  Acidity increases with increase in the number of halogen atoms on  - position.
–  It decreases with increasing distance of halogen from   
–  It increases with increase in the electronegativity of halogen.
- CF3COOH > CCl3COOH > HCOOH > CH3 COOH

A strong base can abstract an α – hydrogen from
  • a)
    Alkane.
  • b)
    Amine
  • c)
    Ketone
  • d)
    Alkene
Correct answer is option 'C'. Can you explain this answer?

Vijay Bansal answered
After deprotonation the negative charge will be in conjugation with the pi orbital of carbonyl..so base will prefer to abstract alpha hydrogen from ketone.

The appropriate reagent for the transformation:
  • a)
    NaBH4
  • b)
    NH2NH2, OH-
  • c)
    Zn(Hg), HCl
  • d)
    H2, Ni
Correct answer is option 'B'. Can you explain this answer?

In this reaction, a CO group is converted to CH2​ group.
This can be achieved by Wolff-Kishner reduction which uses reagent NH2​NH2​, OH (hydrazine in alkaline medium).

Clemmensen reduction (Zn(Hg)/HCl) cannot be used as in presence of HCl, the alcohol may undergo dehydration.

Chapter doubts & questions for Aldehydes, Ketones and Carboxylic Acids (OC) - MCAT Chemical and Physical Foundations 2025 is part of MCAT exam preparation. The chapters have been prepared according to the MCAT exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for MCAT 2025 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.

Chapter doubts & questions of Aldehydes, Ketones and Carboxylic Acids (OC) - MCAT Chemical and Physical Foundations in English & Hindi are available as part of MCAT exam. Download more important topics, notes, lectures and mock test series for MCAT Exam by signing up for free.

Top Courses MCAT