Concentrations of Iron II Sulfate

Question

There are 2 solutions of Iron II Sulfate, both being of different concentratons. The solutions are labeled B and C.
25cm3 of B is poured into testtube labeled B and 25cm3 of C is poured into testtube labeled C.
It takes 13cm3 of Potassium Manganate to colourize 25cm3 of B.
It takes 39cm3 of Potassium Manganate to colouroze 25cm3 of C.

Which soluion of Iron Sulphate is more concentrated?

Answer 1

Iron II Sulphate reacts with potassium manganate.  The first thing you need is a balanced equation.

 

FeSO₄ +  K₂MnO₄  ----> FeMnO₄ + K₂SO₄ (a double displacement reaction)

 

Since we're not given the concentration of potassium manganate to use the formula C₁V₁ = C₂V₂, we have to think theoretically. We expect a 1:1 ratio based on the balanced equation.

 

So, LESS potassium manganate is required for solution B than C, which means solution B is LESS concentrated than solution C.