The %Fe( Mr=55.845g/mol) in a vitamin tablet was determined by dissolving the tablet ( mass=0.1512g) in water. The solution was qualitatively transferred to a 250.0 ml volumetric flask. 20.00 ml of the solution was pipetted into a 200 ml flask. Enough buffer and 1,10-phenanthroline was added and the solution was made up to the mark with water. The Fe^2+ was determined from a calibration curve as 4.21mg/L. Calculate the % Fe in the tablet.

Question

The %Fe( Mr=55.845g/mol) in a vitamin tablet was determined by dissolving the tablet ( mass=0.1512g) in water. The solution was qualitatively transferred to a 250.0 ml volumetric flask. 20.00 ml of the solution was pipetted into a 200 ml flask. Enough buffer and 1,10-phenanthroline was added and the solution was made up to the mark with water. The Fe^2+ was determined from a calibration curve as 4.21mg/L. Calculate the % Fe in the tablet.

Answer 1

First, we need to calculate the concentration of Fe^2+ in the solution pipetted into the 200 ml flask.

Concentration of Fe^2+ = (4.21 mg/L) x (20 ml) / (200 ml)
Concentration of Fe^2+ = 0.42 mg/L

Next, we need to calculate the amount of Fe^2+ in the 20 ml solution pipetted.

Amount of Fe^2+ = (0.42 mg/L) x (20 ml)
Amount of Fe^2+ = 8.4 mg

Now, we need to calculate the amount of Fe in the entire tablet.

Amount of Fe in tablet = (8.4 mg) x (250 ml) / (20 ml)
Amount of Fe in tablet = 105 mg

Now, we can calculate the percentage of Fe in the tablet.

% Fe = (105 mg) / (0.1512 g) x 100
% Fe = 69503.97%

Therefore, the % Fe in the vitamin tablet is approximately 69,504%.