Question

determine the volume of a 0.530 M KMno4 solution required to completely reast with 2.6 g of zn

Answer 1

i try and i got 75.02 mL . but wrong. is it I doing wrong?

Answer 2

Can u write the equations?

Answer 3

I mean just the ionic equations...

Answer 4

Ok see since nothing is mentioned i assume the reaction is carried out in a neutral medium, that means Mn reduces it state from +7 to +4.
And Zinc is oxidized from 0 to +2.
ok?

Answer 5

Given is 2Mno4- + 8H+ + 5Zn -> 2Mn2+ + H2O +5Zn2+

But i dont see K there, so i dont know if i can use this..

Answer 6

Ah ok so now just observe the coeffecients of Mn and Zn in the reactants the rest is useless.
Mn coeffecient-2. Zn-5.
Do you know law of equivalents? M1V1e1=M2V2e2

Answer 7

yes.. i knew it..
im using that just know, but got the wrong answer.

Answer 8

Well actually in this reaction which is a redox reactions only the ions which undergo a change in oxidation state matter.If you see Mn on the left you have it in +7 oxidation state but on the right it is in +2 so e1=5.
Now Zn changes from 0 to +2 so its e2=2. Now M2 V2 of zinc is nothing but the number of moles of Zn=2.6/65.38=0.04
So 5*x*0.53=0.04*2. You get x as 0.0301L which is 30.1mL

Answer 9

M1V1=n2 .. ok, i got it..