PMDC Verified Question 56 of 83
The type of isomerism existing in a compound of molecular formula \( \text{C}_2\text{H}_6\text{O} \) is:
A
Functional group
B
Position
C
Chain
D
Metamerism
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Functional group
Concept:

Functional group isomerism occurs when two molecules share a molecular formula but belong to entirely different chemical families (have different functional groups).

Solution:

  • The formula \( \text{C}_2\text{H}_6\text{O} \) corresponds to the general formula \( \text{C}_n\text{H}_{2n+2}\text{O} \), which characterizes saturated alcohols and ethers.


  • It can be drawn as:
    • Ethanol: \( \text{CH}_3\text{CH}_2\text{OH} \) (Alcohol)
    • Dimethyl ether: \( \text{CH}_3\text{--O--CH}_3 \) (Ether)


  • Since the functional group changes completely, this is functional group isomerism.


Why other options are incorrect:

Position and chain isomerism require the functional group to remain the same. Metamerism requires a polyvalent functional group with at least 4 carbons to show different alkyl distributions.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

Want to solve full-length papers under timed exam conditions?

Practice with zero-scroll lockdown sprints, dynamic latency zone timers, live peer selection telemetry, and the automated Amber mistake recovery loop.