Question

A) number of moles of I2 produced from 25ml of diluted KIO3

B) number of moles of Na2S2O3 added in titration

C) number of moles of I2 used by the Na2S2O3

What we know:

Molar concentration of diluted KIO3- 0.0018mol/L

Molar concentration of Na2S2O3 0.016

Initial Burrette reading of 5.48 ml and final reading 22.59 ml

Answer 1

It is an iodometry titration.

a) ICIO3 react with KI in presence of acid to give Iodine gas.

6H⁺ + IO₃^- + 5I^- ------> 3I₂ + 3H₂O

i.e 1 mole of ICIO₃ gives 3 moles of I2

Molar concentration of diluted KIO₃ = 0.0018M

Volume of ICIO₃ = 25 mL = 0.025L

therefore Moles of ICIO₃ used = Molarity x volume

= 0.0018 moll-1 x 0.025L

= 4.5 x 10-5 moles

as 1 mole of KIO₃ produce 3 mole of I2

Therefore 4.5 x 10^-5 mole KIO₃ will produce

= 4.5 x 10^-5 x 3 mole of I2

Moles of I₂ produced = 0.000135 mole of I₂