JEE Main 2022 · ChemistryMultiple choiceSingle correctMediumConceptual

JEE Main 29 July 2022, Shift 2, Chemistry Q70

Question 70 of 90 in this shift, Chemistry question 10 of 30, Section A.

Which of the following 3d-metal ion will give the lowest enthalpy of hydration (

\Delta_{hyd}H

) when dissolved in water ?

(1) $\mathrm{Cr^{2+}}$
(2) $\mathrm{Mn^{2+}}$ Official answer
(3) $\mathrm{Fe^{2+}}$
(4) $\mathrm{Co^{2+}}$

Official answer

Option 2

NTA final key.

Chapter: The d- and f-Block Elements
Topic: Crystal Field Theory
Idea tested: CFSE and Hydration Enthalpy Double-Hump

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Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.