JEE Main 2026 — Chemistry Physical Chemistry

2026mcqmedium

Given below are two statements :

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 $\mathrm{He}^{+}$ 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 :

Official previous-year question

Held on 21 Jan 2026 · Verified 6 Jul 2026.

Options

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

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Solution

Statement I: Electric discharge through $H_2$ causes dissociation into excited H atoms which emit discrete frequencies (line spectrum). This is true.

Statement II: Using $\nu = RcZ^2\left(\frac{1}{n_1^2} - \frac{1}{n_2^2}\right)$

For $He^+$ (Z=2), second Balmer line ( $n_1=2, n_2=4$ ): $\nu = 4Rc\left(\frac{1}{4} - \frac{1}{16}\right) = \frac{3Rc}{4}$

For H (Z=1), first Lyman line ( $n_1=1, n_2=2$ ): $\nu = Rc\left(1 - \frac{1}{4}\right) = \frac{3Rc}{4}$

Both frequencies are equal. Statement II is true.

Both statements are true.

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Solution

Statement I: Electric discharge through $H_2$ causes dissociation into excited H atoms which emit discrete frequencies (line spectrum). This is true.

Statement II: Using $\nu = RcZ^2\left(\frac{1}{n_1^2} - \frac{1}{n_2^2}\right)$

For $He^+$ (Z=2), second Balmer line ( $n_1=2, n_2=4$ ): $\nu = 4Rc\left(\frac{1}{4} - \frac{1}{16}\right) = \frac{3Rc}{4}$

For H (Z=1), first Lyman line ( $n_1=1, n_2=2$ ): $\nu = Rc\left(1 - \frac{1}{4}\right) = \frac{3Rc}{4}$

Both frequencies are equal. Statement II is true.

Both statements are true.

JEE Main 2026 — Chemistry Physical Chemistry

Options

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Solution

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JEE Main 2026 — Chemistry Physical Chemistry

Options

Did you get this right?

Solution

Your note

JEE Main Physical Chemistry in other years

More JEE Main Physical Chemistry questions

Other Chemistry topics for JEE Main

Organic Chemistry

Inorganic Chemistry

Keep practicing Physical Chemistry