JEE Main 2025 · 22 January · evening · Single correct · +4 / −1

Given below are two statements :
Statement (I) : A spectral line will be observed for a 2 pₓ → 2 p_y transition.
Statement (II) : 2 pₓ and 2 p_y are degenerate orbitals.
In the light of the above statements, choose the correct answer from the options given below :

  1. (a) Statement I is false but Statement II is true
  2. (b) Both Statement I and Statement II are false
  3. (c) Statement I is true but Statement II is false
  4. (d) Both Statement I and Statement II are true
Answer and solution

Answer (a) Statement I is false but Statement II is true

Solution

Chemistry ma’am · 4 steps

A spectral line needs an energy gap, and 2pₓ and 2p_y sit at exactly the same energy.

  1. Where lines come from. A spectral line appears when an electron moves between two levels of different energy. It gives out or takes in a photon of energy Δ E = hν.
  2. Check Statement II. 2pₓ and 2p_y have the same n = 2 and l = 1 and differ only in orientation. With no external field they have equal energy, so they are degenerate. Statement II is true.
  3. Check Statement I. For a jump between degenerate orbitals, Δ E = 0, so ν = 0 and no photon is produced. No spectral line is seen, so Statement I is false.
  4. So. Statement I is false and Statement II is true, which is option (a).

The idea to keep. No energy difference means no photon and no line. Orbitals in the same subshell are degenerate (in the absence of a field), so jumps between them are spectrally silent.

Answer from the NTA final answer key. Solution by PrepWiser.

Study Atomic Structure

Asked about 170 times in JEE Main since 2020. This question is from 2025.