Question

You carried out the standardization of a potassium permanganate, KMnO4, solution using the procedure described in this laoratory experiment.

mass of sodium oxalate, Na2C2O4.........0.2783

potassium permanganate (KMnO4) solution:

initial buret reading.......0.72mL

final buret reading........33.84mL

(b) Calculate the number of moles of Na2C2O4.

(c) Calculate the number of moles of KMnO4

(d) Calculate the molarity of the KMnO4

Please show all work

Answer 1

B.

The number of moles of Na2C2O4

Given that amount of sodium oxalate, Na2C2O4= 0.2783 g

Number rof mole s= amount in g / molar mass

= 0.2783 g/ 133.998 g/mol

= 2.1*10^-3 mole Na2C2O4

(c) Calculate the number of moles of KMnO4

The balance reaction is as follows:

5Na2C2O4 + 2KMnO4 + 8H2SO4 → 10CO2 + 8H2O + 5Na2SO4 + 2MnSO4 + K2SO4

Now calculate the mole of KMnO4 as follows:

2.1*10^-3 mole Na2C2O4 * 2 mole KMnO4 / 5 mole Na2C2O4

= 8.31*10^-4 mole KMnO4

(d) Calculate the molarity of the KMnO4

Given that

initial buret reading.......0.72mL

final buret reading........33.84mL

volume of KMnO4 = 33.84 ml – 0.72 ml

= 33.12 ml

= 0.03312 L

Molarity = number of mole s/ volume in L

= 8.31*10^-4 mole KMnO4/ 0.03312 L

= 0.025 M