JEE Main 2020ChemistryClassification of Elements and Periodicity in PropertiesEasyMCQ

JEE Main 2020 — Classification of Elements and Periodicity in Properties Question with Solution

JEE Main 2020 (09 Jan Shift 2)

Question

The first and second ionisation enthalpies of a metal are 496 and 4560 kJ mol-1, respectively. How many moles of HCl and H2SO4, respectively, will be needed to react completely with 1 mole of the metal hydroxide?

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Show full solutionCorrect option: D
Correct answer
D1 and 0.5

Step-by-step explanation

Ionization Enthalpy values indicate that the metal belongs to Ist group, since the second ionization enthalpy is very high.
(Q - only one valence electron)
Metal hydroxide will be of the type, MOH.

MOH 1 mol + HCl 1 mol →MCl+ H 2 O

MOH+ 1 2 H 2 SO 4 → 1 2 M 2 SO 4 + H 2 O

(1mol) 1 2 mol So, one mole of HCl is required to react with one mole of MOH.

So, 1 2 mole of H 2 SO 4  is required to react with one mole of MOH.

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About this question

This is a previous-year question from JEE Main 2020, covering the Classification of Elements and Periodicity in Properties chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.