Chemistry · Structure of Atom

JEE Main 2026 — 21 January, Morning Shift — Question 62

Given below are two statements, one is labelled as Statement I and the other is labelled as Statement II.

Statement I: When an electric discharge is passed through gaseous hydrogen, the hydrogen molecules dissociate and the energetically excited hydrogen atoms produce electromagnetic radiation of discrete frequencies.

Statement II: The frequency of second line of Balmer series obtained from He+\mathrm{He}^{+} is equal to that of first line of Lyman series obtained from hydrogen atom.

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

  1. Option A:

    Both Statement I and Statement II are true

    Correct
  2. Option B:

    Both Statement I and Statement II are false

  3. Option C:

    Statement I is false but Statement II is true

  4. Option D:

    Statement I is true but Statement II is false

Answer: A

Step-by-step solution

Statement I: Electric discharge dissociates H2\mathrm{H_2} into atoms. Excited atoms emit radiation during electronic transitions, producing discrete spectral lines. Hence, Statement I is true.

Statement II: Second Balmer line of He+\mathrm{He^+}:

Z=2,  4→2Z = 2,\; 4 \to 2 \left(\frac{1}{2^2} - \frac{1}{4^2}\right)$$ $$\bar{\nu}_1 = 4R \left(\frac{1}{4} - \frac{1}{16}\right)$$

\bar{\nu}_1 = \frac{3R}{4}

First Lyman line of hydrogen is $2 \to 1$ $$\bar{\nu}_2 = R \left(1 - \frac{1}{4}\right) = \frac{3R}{4}$$ Thus $\bar{\nu}_1 = \bar{\nu}_2$. Frequencies are equal. Hence, Statement II is true.

Answer key and solution verified before publishing.

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Exam
JEE Main 2026
Subject
Chemistry
Chapter
Structure of Atom
Topic
Analysis of Spectra of H-like species
Given below are two statements, one is labelled as Statement I and… | JEE Main 2026 PYQ with Solution · DhiX AI