MDCAT Chemistry — Aldehydes and Ketones
Aldehydes and Ketones is a core Chemistry topic in the PMDC MDCAT syllabus, covering 7 subtopics. Below are the subtopics to revise, how often the topic appears in past papers, and real past-paper MCQs to try.
Subtopics (7)
- Nomenclature and Structure
- Nucleophilic Addition Reactions
- Oxidation Reactions
- Preparation
- Reactivity of Aldehydes and Ketones
- Reduction to Alcohols
- Tests for Aldehydes (Fehling's, Tollens')
How Aldehydes and Ketones is tested
Across the 16 MDCAT past papers on ParhaiKrlo, Aldehydes and Ketones accounts for 36 questions. It appears in all 16, about 2.3 questions a paper. The heaviest was MDCAT 2019, with 5 questions, and the most recent is MDCAT 2025, with 2.
| Paper | Questions |
|---|---|
| MDCAT 2025 | 2 |
| MDCAT 2024 | 1 |
| MDCAT 2023 | 2 |
| MDCAT 2022 | 2 |
| MDCAT 2019 | 5 |
| MDCAT 2018 | 2 |
| MDCAT 2017 | 1 |
| MDCAT 2016 | 2 |
| MDCAT 2015 | 1 |
| MDCAT 2014 | 2 |
| MDCAT 2013 | 3 |
| MDCAT 2012 | 4 |
| MDCAT 2011 | 4 |
| MDCAT 2010 | 1 |
| MDCAT 2009 | 2 |
| MDCAT 2008 | 2 |
Aldehydes and Ketones MCQs from the MDCAT past papers
Try each one before opening the answer. Each comes with a short explanation.
- Q1 · MDCAT 2025 · Aldehydes and Ketones
Acetaldehyde undergoes oxidation to produce acetic acid. In this reaction, the oxidizing agent used is:
- A.HI
- B.LiAlH₄
- C.K₂Cr₂O₇
- D.NaBH₄
Show answer
Answer: C. K₂Cr₂O₇ — K2Cr2O7 (potassium dichromate) oxidizes acetaldehyde to acetic acid.
- Q2 · MDCAT 2024 · Aldehydes and Ketones
The blue color of Fehling solution is changed to red when warmed with an aldehyde due to formation of which of the following?
- A.NO₂
- B.Cu₂O
- C.AgO
- D.SO₂
Show answer
Answer: B. Cu₂O — Fehling's test turns from blue to a red precipitate of Cu2O when it reacts with an aldehyde.
- Q3 · MDCAT 2023 · Aldehydes and Ketones
The appearance of a silver mirror in Tollens' test indicates the presence of which of the following?
- A.A ketone
- B.An aldehyde
- C.An acid
- D.An alcohol
Show answer
Answer: B. An aldehyde — A positive Tollens' test (silver mirror) indicates the presence of an aldehyde.