Chemistry Equilibrium ETEA 2024
PMDC Verified Question 14 of 102
The \( \text{pK}_a \), of n-propyl amine is
A
3.24
B
3.28
C
3.32
D
3.35
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: 3.32
Concept:

Note: The question text uses the term "\( \text{pK}_a \)" but chemically provides the literature value for the \( \text{pK}_b \) of n-propylamine. Amines are bases.

Solution:

  • Amines are basic organic compounds. The strength of their basicity is measured by their base dissociation constant, \( K_b \), or its negative log, \( \text{pK}_b \).


  • n-propylamine (\( \text{CH}_3\text{CH}_2\text{CH}_2\text{NH}_2 \)) is a primary aliphatic amine.


  • Historical textbook data and chemical tables list its \( \text{pK}_b \) value as exactly 3.32.


  • (For strict accuracy: its actual \( \text{pK}_a \) as a conjugate acid is ~10.68. The exam question contained a typo but 3.32 is the universally expected answer key for this specific rote-memorization metric.)


Why other options are incorrect:

These are simply incorrect numerical values for this specific constant.

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.

Previous Question All Equilibrium MCQs Next Question

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.

Enter Arena Sprint iOS App Android App