Question

A sample of Fe2(SO4)3 and FeC204 was dissolved in dil. T
H.SO . The complete oxidation of reaction mixture required
40ml of N/16 KMnO4. After the oxidation, the reaction
mixture was reduced by Zn and dil. H2SO4. On again
oxidation by same KMnO4, 60ml were required. The ratio
of millimoles of Fe2(SO4)3 and FeC204 is 7:A. Find the
value of A. (mol wt. Fe2(SO4)3 = 400).
(A) 4
(B)3
(C)2
(D) 1
Answer is 4 plz explain how it came ​

Answer 1

Answer:

Explanation:

let millimoles of  ferric sulphate and millimoles of ferrous oxylate be a and b

let equivalent of fec2o4 =x

then equivalent of fe+2 = x

equivalent of c2o4-2 = x

then

equivalent of fe+2 + equivalent of c2o4-2 = 40/16

2x=40/16

x=40/32

we all know that zinc is reducing agent

so (fe+3)1+(fe+3)2 = 60/16

40/32+fe+3 starting = 60/16

fe+3 starting = 40/16

we have calculate equivalent

moles *f = 40/16

moles = 40/96

moles*f=40/16

moles=40/32

moles 1/moles 2 = 1/3

7/a=1/3

a=21