0.1200 g of potassium dichromate primary standard is dissolved, quantitatively transferred into a 250-mL volumetric flask...

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Chemistry

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.

Answer & Explanation Solved by verified expert

3.9 Ratings (626 Votes)

Solution Balanced redox equation for the reaction between the iron ll ion and potassium dichromate is as follows K2Cr2O7 6Fe2aq14Haq 2Cr3aq 6Fe3aq7H2Ol2Kaq The mole See Answer

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