0.1200 g of potassium dichromate primary standard is dissolved,quantitatively transferred into a 250-mL volumetric flask anddiluted to volume. 0.3000 g an unknown iron ore sample wasdissolved in hydrochloric acid, treated with stanous chloride andmercury(II) chloride, quantitatively transferred to a 100-mLvolumetric flask and diluted to volume. 25.00 mL of the unknowniron(II) solution was pipetted into 500-mL Erlenmyer flask andtitrated with the potassium dichromate solution. 28.00 mL ofpotassium dichromate is required to reach the end point.
Calculate the moles of iron(II) in the original unknownsample.
I've tried:
0.3000g * (1 mol /55.845g) = 0.005372 mol Fe(2)
but it says it's a wrong answer.
