Chemistry Fundamental Principles of Organic Chemistry ETEA 2023
PMDC Verified Question 24 of 83
Identify the molecular formula of Furan:
A
\( \text{C}_4\text{H}_4\text{O} \)
B
\( \text{C}_3\text{H}_4\text{O} \)
C
\( \text{C}_6\text{H}_5\text{O} \)
D
\( \text{C}_4\text{H}_5\text{O} \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: \( \text{C}_4\text{H}_4\text{O} \)
Concept:

Furan is a five-membered heterocyclic, aromatic organic compound containing one oxygen atom in the ring.

Solution:

  • The ring consists of 4 carbon atoms and 1 oxygen atom.


  • To satisfy aromaticity (Huckel's rule), the ring contains two double bonds among the carbon atoms.


  • This means each of the four carbon atoms forms three internal ring bonds (two single, one double) and is bonded to exactly one hydrogen atom.


  • Thus, the molecular formula is \( \text{C}_4\text{H}_4\text{O} \).


Why other options are incorrect:

Option B has too few carbons. Option C resembles the formula for the phenoxide ion or a radical. Option D has an incorrect hydrogen count, violating the tetravalency of the aromatic carbons.

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.

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