Use Coupon: CART20 and get 20% off on all online Study Material

Total Price: Rs.

There are no items in this cart.
Continue Shopping
Grade: 11
Eq.wt of MnO4^- in acidic, basic and neutral medium are in which ratio?A) 3:5:15B) 5:3:1C) 5:1:3D) 3:15:5(Explain in detail)
10 months ago

Answers : (3)

24734 Points
KMnO4 has a Molar mass of 158.04 g/mol 

There are two possibilities: 

1. KMnO4 as an oxidizer in acidic media:
MnO4- + 8 H+ + 5e- --> Mn2+ + 4H2O (gained 5 electrons from reductant) 

I.e. 5 Equivalents per mole, so equivalent mass of KMnO4 = M/5 = 158.04/5 = 31.61 gram/equivalent 

2. KMnO4 as an oxidizer in neutral or basic media:
MnO4- + 2H2O + 3e- --> MnO2(s) + 4OH- (gained 3 electrons) 

In this case: 3 equivalents per mole, so equivalent mass of KMnO4 = M/3 = 158.04/3 = 52.68 gram/equivalent
10 months ago
Vikas TU
11685 Points
Dear student 
In Acidic medium, This Mn+7 goes to Mn+2 state and hence there is a net gain of 5 electrons. 
Now, equivalent weight = [molar mass] /[number of electrons gained or lost]
so, eq wt = 158/5 = 31.6 g.
Now, for alkaline medium, there are two possibilities
1) faintly alkaline/neutral:
 Mn+7 changes into Mn+4 therefore, gain of 3 electrons
 Hence, eq wt = 158/3 = 52.67g
2) highly alkaline:
 Mn+7 changes into Mn+6 therefore, gain of 1 electron
 Hence, eq wt = 158/1 = 158g
In many cases though if it's written alkaline, it mostly means the neutral one; for the highly alkaline thing, it'll especially mention it.
10 months ago
Shadic The Hedgehog
23 Points
Sir, then, which ratio is it in? Can you explain the ratios?
Because I can’t understand the ratio part. Help Please.
10 months ago
Think You Can Provide A Better Answer ?
Answer & Earn Cool Goodies

Course Features

  • 731 Video Lectures
  • Revision Notes
  • Previous Year Papers
  • Mind Map
  • Study Planner
  • NCERT Solutions
  • Discussion Forum
  • Test paper with Video Solution

Course Features

  • 141 Video Lectures
  • Revision Notes
  • Test paper with Video Solution
  • Mind Map
  • Study Planner
  • NCERT Solutions
  • Discussion Forum
  • Previous Year Exam Questions

Ask Experts

Have any Question? Ask Experts

Post Question

Answer ‘n’ Earn
Attractive Gift
To Win!!! Click Here for details