Chemistry Equilibrium ETEA 2016
PMDC Verified Question 90 of 102
\( K_p = K_c(RT) \) in the equation if \( \Delta n < 0 \) then:
A
\( K_p = K_c \)
B
\( K_p < K_c \)
C
\( K_p > K_c \)
D
\( K_p < 0 \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: \( K_p < K_c \)
Concept:

The mathematical relationship between \( K_p \) and \( K_c \) depends heavily on the sign of \( \Delta n \) (change in gas moles).

Formula:

$$ K_p = K_c (RT)^{\Delta n} $$

Solution:

  • If \( \Delta n < 0 \) (negative), the term \( (RT)^{\Delta n} \) becomes a fraction \( \frac{1}{(RT)^{|\Delta n|}} \).


  • Assuming \( RT > 1 \) (which is true for standard thermodynamic temperatures in Kelvins), multiplying \( K_c \) by a fraction less than 1 yields a smaller number.


  • Therefore, \( K_p \) will be less than \( K_c \).


Why other options are incorrect:

\( K_p = K_c \) requires \( \Delta n = 0 \). \( K_p > K_c \) requires \( \Delta n > 0 \). Equilibrium constants cannot be negative (eliminating D).

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