Chemistry S & P Block Elements DUHS 2024
PMDC Verified Question 15 of 104
The alkali metal gives a yellow color during a flame test is:
A
Ba
B
K
C
Na
D
Cs
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Na
Concept:

The flame test identifies metal cations based on the specific wavelength (color) of light emitted when their thermally excited electrons relax to the ground state.

Solution:

  • When introduced into a Bunsen burner flame, different elements emit unique colors.
  • Sodium (Na) has an emission spectrum dominated by the "Sodium D-lines" at approximately 589 nm.
  • This specific wavelength corresponds to a very intense, persistent, bright yellow-golden color.
  • (This is the same principle behind the bright yellow glow of sodium vapor streetlights).


Why other options are incorrect:

  • Ba: Is an alkaline earth metal (not an alkali metal) and imparts a pale green color.
  • K: Imparts a lilac/violet color.
  • Cs: Imparts a blue/violet color.

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 S & P Block Elements 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