[Namossa]

Hi I have a question concerning this?

An acidified Fe²⁺ solution was titrated with permanganate solution. When titrated went 20 cm^3 0.02020 mol/dm^3 MnO₄ solution. Determine the amount Iron expressed in gram in the first solution?

Here are my calculations
5Fe²⁺ (aq) + MnO₄- (aq) + 8H+ --> 5Fe³⁺ (aq)+ Mn²⁺ + 4H₂O

Fe Molar mass 55,935 g/mol

n=c * (V/1000)

0.02020 * (20/1000) 4*10^-4

Ratio MnO₄: Fe²⁺
1:5

4* 10^-4 * 5 =2,02 *10^-3

2,02 *10^-3* 55,935= 0.1129887 g

The correct answer is 0.01127g

What I am doing wrong
please help
Thank you!

[chenbeier]

Determine the amount Iron expressed in gram in the first solution?

What does it mean. Your calculation for the 20 cm³ is correct, but was this sample taken from something ?

[Namossa]

It was not written in the question.

Any more comments?

Thanks!

[chenbeier]

Then it can be  only 2 cm³ solution or it was 0,00202 mol/l concentration.

[Namossa]

I solved it thx!

[chenbeier]

What was the reason now?