Chemistry S & P Block Elements SZABMU 2024
PMDC Verified Question 9 of 104
The color imparted by the Li wire when subjected to flame is
A
Crimson red
B
Pale green
C
Greyish white
D
Brick red
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Crimson red
Concept:

The flame test identifies specific metal cations based on the unique wavelength of visible light emitted when their heat-excited electrons fall back to the ground state.

Solution:

  • Different metals have distinct, quantized energy gaps between their electron orbitals.
  • When Lithium (Li) is heated in a flame, its valence electrons absorb thermal energy and jump to higher orbitals.
  • Upon returning to their lower energy state, they release energy in the form of a photon.
  • For Lithium, the energy gap corresponds perfectly to a wavelength in the red part of the visible spectrum.
  • Thus, Lithium imparts a brilliant Crimson red color to the flame.


Why other options are incorrect:

  • Pale green: Characteristic of Barium (Ba).
  • Brick red: Characteristic of Calcium (Ca).
  • Greyish white: Not a standard flame test color (often associated with burning Mg metal, but not as a wire salt test).

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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