SATHEE: Some Basic Concepts of Chemistry

Some Basic Concepts of Chemistry - Result Question 12

####12. Number of moles of $M n O_{4}^{-}$ required to oxidize one mole of ferrous oxalate completely in acidic medium will be :

(a) 0.6 moles

(b) 0.4 moles

(d) 0.2 moles

[2008]

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Solution:

From above equation 2 moles of $M n O_{4}$ required to oxidise 5 moles of oxalate.

Thus number of moles of $M n O_{4}^{-}$ required to oxidise one mole of oxalate $= 2 \times 2 / 5 = 0.4$ moles

In $K M n O_{4}$ the oxidation state of $M n$ is +7 . In acidic medium Mn takes up five electrons and making it an oxidizing agent. In strongly alkaline solution it takes up only 1 electrons and making it much weaker oxidising agent. In neutral medium it gives up 3 electrons to form $M n O_{2}$ Acidic medium:

$M n O_{4}^{-} + 8 H^{+} + 5 e^{-} \to M n^{2 +} + 4 H_{2} O$

Alkaline medium: $M n O_{4}^{-} + e^{-} \to M n O_{4}^{2 -}$

Neutral medium:

$M n O_{4}^{-} + 4 H^{+} + 3 e^{-} \to M n O_{2} + 2 H_{2} O$

Some Basic Concepts of Chemistry - Result Question 12

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Some Basic Concepts of Chemistry - Result Question 12

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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