JEE Main 2018 — D And F Block Elements Question with Solution
From: JEE Main 2018 (Online) 16th April Morning Slot
Question
When XO2 is fused with an alkali metal hydroxide in presence of an oxidizing agent such as KNO3 ; a dark green product is formed which disproportioates in acidic solution to afforda dark purple solution. X is :
Choose an option
Show full solutionCorrect option: D
Correct answer
DMn
Step-by-step explanation
X is Mn.
MnO2 + 2KOH + KNO3 K2MnO4 + KNO2 + H2O
Here K2MnO4 is dark green.
3MnO42 + 4H+ 2MnO4 + MnO2 + 2H2O
In acidic solution, K2MnO4 changes to dark purple solution of KMnO4.
MnO2 + 2KOH + KNO3 K2MnO4 + KNO2 + H2O
Here K2MnO4 is dark green.
3MnO42 + 4H+ 2MnO4 + MnO2 + 2H2O
In acidic solution, K2MnO4 changes to dark purple solution of KMnO4.
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This is a previous-year question from JEE Main 2018, covering the D And F Block Elements 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.