Question

Balance the following redox reaction:

_ _ _ _ _ _ + _ _ IO3- + _ _ I- --> _ _ I2 + _ _   _ _ _ _

Calculate the mass of the vitamin C (in mg) in the tablet. ( use balanced equation from above)

Standardized KIO3 (M) = 0.010

initial KIO3 Buret volume (mL) = 0.2

Final KIO3 buret Volume (mL) = 20.39

Calculate COV

Trial       Mass of Vitamin C

1            94.6

2            108.2

3             93.9

4             109.2

5           108.1

6            94.5

Answer 1

Balanced equation is : C₆H₈O₆ + 4 H⁺ + IO₃^- + 3 I^- C₆H₆O₆ + 2 I₂ + 3 H₂O

where C₆H₈O₆ is vitamin C

Total volume of KIO₃ used = final volume - initial volume

Total volume of KIO₃ used = 20.39 mL - 0.2 mL

Total volume of KIO₃ used = 20.19 mL

Total volume of KIO₃ used = 20.19 x 10^-3 L

moles of KIO₃ used = (molarity of KIO₃) * (Total volume of KIO₃ used)

moles of KIO₃ used = (0.010 M) * (20.19 x 10^-3 L)

moles of KIO₃ used = 2.019 x 10^-4 mol

moles of vitamin C present = moles of KIO₃ used

moles of vitamin C present = 2.019 x 10^-4 mol

mass of vitamin C = (moles of vitamin C present) * (molar mass of vitamin C)

mass of vitamin C = (2.019 x 10^-4 mol) * (176.12 g/mol)

mass of vitamin C = 0.03556 g

mass of vitamin C = 35.56 mg