Topic: Modern periodic law and periodic table, s, p, d, f blocks· Classification of Elements and Periodicity in Properties

Identify the incorrect statement from the following

1. Lithium is the strongest reducing agent among the alkali metals.

2. Alkali metals react with water to form their hydroxides.

3. The oxidation number of K in \(KO_2\) is \(+4\).

4. Ionisation enthalpy of alkali metals decreases from top to bottom in the group.

Doubtly Asked 30 Oct 2026 NEET UG 2022 neet Save WhatsApp Report

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Answer: 3. The oxidation number of K in \(KO_2\) is \(+4\).

Key idea: in superoxide \(\mathrm{KO_2}\), oxygen is \(\mathrm{O_2^-}\), so K is +1.

Alkali metals always show +1. The charge on K in \(\mathrm{KO_2}\) is +1, not +4, so statement 3 is incorrect.

Others are true: Li has the most negative \(E^\circ\) (strongest reducing agent in water), alkali metals give hydroxides with water, and ionisation enthalpy falls down the group.

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

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Identify the incorrect statement from the following

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