Verified Solution • 2025–26 Session moderate

QJEEM25Ch2bda: JEE Main 2025 Chemistry - Class 11 JEEM25Ch2bda Solution: Given below are two statements : Statement (I) : A spectral…

Given below are two statements :

Statement (I) : A spectral line will be observed for a 2px→2py2 p_x \rightarrow 2 p_y transition.

Statement (II) : 2px2 \mathrm{p}_x and 2py2 \mathrm{p}_y are degenerate orbitals.

In the light of the above statements, choose the correct answer from the options given below :

Multiple Choice Options

  • A Statement I is false but Statement II is true
  • B Both Statement I and Statement II are false
  • C Statement I is true but Statement II is false
  • D Both Statement I and Statement II are true

Step-by-Step Verified Solution

Let us analyze the two statements in the context of atomic orbitals and electronic transitions:


Statement (I)

“A spectral line will be observed for a 2px→2py2 p_x \rightarrow 2 p_y transition.”

For an emission (or absorption) line to be observed, there must be a difference in energy between the initial and final states.

In a typical hydrogen-like or many-electron atom (without additional external fields or splitting effects), the three 2p2p orbitals ( 2px2 p_x , 2py2 p_y , 2pz2 p_z ) are degenerate—i.e., they all have the same energy.

Consequently, a transition from 2px2 p_x to 2py2 p_y (both having the same energy) would involve no energy change. Hence, no photon is emitted or absorbed for this “transition.” So you would not observe a spectral line for such a transition.

Therefore, Statement (I) is false.


Statement (II)

“ 2px2 p_x and 2py2 p_y are degenerate orbitals.”

Orbitals within the same subshell (e.g., 2p2p subshell) are typically degenerate (same energy) in an isolated atom (especially a hydrogen-like atom).

Thus, 2px2 p_x and 2py2 p_y (and 2pz2 p_z ) do indeed have the same energy.

Therefore, Statement (II) is true.


Conclusion

Statement (I): False

Statement (II): True

Hence, the correct choice is:

Option A: Statement I is false but Statement II is true.

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