Question

The number of moles of mno4- reduced to mn+2 by the addition of 7.5 mole electron in mno4-  is 

A)2.5 

B)5 

C)1.5 

D) 7.5 

Answer 1

OPTION (C) IS CORRECT

Ionic redox reaction mentioned here is represented by the following  balanced equation
\( {MnO_4^- + 8H^+ +5e=Mn^{2+} +4H_2O}\)

Here it is obvious  from the equation  that 5mole electron is required for reducion of one mole Manganate ions. Hence 7.5mole electrons Wil be required for 1.5mole manganate ions to be reduced.