JEE Main 2013ChemistrySome Basic Concepts of ChemistryMediumMCQ

JEE Main 2013Some Basic Concepts of Chemistry Question with Solution

JEE Main 2013 (07 Apr)

Question

Experimentally it was found that a metal oxide has formula M0.98O. Metal M, is present as M2+ and M3+ in its oxide. Fraction of the metal which exists as M3+ would be:

Choose an option

Show full solutionCorrect option: D
Correct answer
D4.08%

Step-by-step explanation

Consider one mole of the oxide, then

Moles of M = 0.98;     Moles of O2- = 1

Let 'x' moles of M are in +3 oxidation state, then Moles of M2+ = 0.98-x

On doing charge balancing we get 

(0.98 - x)2 + 3x  = 2

Or 1.96 - 2x + 3x - 2 = 0

Or x = 0.04

 ∴ %of M3+=0.040.98×100=4.08%

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About this question

This is a previous-year question from JEE Main 2013, covering the Some Basic Concepts of Chemistry 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.