The Student Room Group
Uni students - Complete our survey >>
Uni students - Complete our survey >>
Uni students - Complete our survey >>

Redox titrations

Question 4 please

So I have this question on redox titration
But I don’t know how to make a chemical equation using this question

Any help please
8BAB9F68-8868-4814-B8F5-7487ED118347.jpg.jpeg
40231288-2799-4357-8EA7-E11391D663FE.jpg.jpeg25.7KB
Reply 1
Avatar for jb2510
jb2510
8
Sry in advance for the crap chemical formulas don't know how to do the equation stuff

Fe2+---->Fe3+ + e
14H+ + Cr2O72- +6e---->2Cr3+ +7H2O
--------------------------------------------------------------------------
6Fe2+ + 14H+ + Cr2O72- ---> 6Fe3+ 2Cr3+ + 7H2O

n(Cr2O72-)= 3.26*10^-5 (use n=cv/1000)
n(Cr2O72-:Fe2+)= 1:6
n(Fe2+)= 6*3.26*10^-5
n(Fe2+)= 1.956*10^-4

ratio of n( in 250cm3) to n(25 cm3)===> n( in 250cm3)/n(25 cm3) = 250/25
ratio of n( in 250cm3) to n(25 cm3)= 10
n(Fe2+) in 250cm3= 1.956*10^-3
m(Fe2+)= 1.956*10^-3* 55.8 (use n=m/Mr)
m(Fe2+)= 0.109 g
%= 0.109/0.940 = 11.6%

Hope this helps
Reply 2
Avatar for Anomalous a
Anomalous a
OP
8
Thank u

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you