Question

The net equation for the Briggs-Rauscher reaction is:

IO₃^- + 2H₂O₂ + H⁺ + CH₂(CO₂H)₂ -------> ICH(CO₂H)₂ + 2O₂ + 3H₂O

From the exact concentrations and amounts of reagents you created and worked with (i.e the volumes when performing the reaction), calculate the grams of oxygen that have been formed when the reaction is complete. What reagent is limiting? Show all work. (NOTE: Volume of Malonic Acid 10mL, volume of Manganese Sulfate Monohydrate 10mL, Potassium Iodate 10mL, 1mL of starch).

Answer 1

Density of KIO3 = 3.89 g mL-1

Density of malonic acid = 1.62 g mL-1

So, mass of KIO3 = density x volume = 3.89 g mL-1x 10 mL = 38.9 g

Similarly,

mass of malonic acid = 1.62 x 10 = 16.2 g

Mol of KIO3 = mass / molar mass

= 38.9 g / 214 gmol-1

= 0.181 mol

Mol of malonic acid = 16.2 g / 104.06 gmol-1

= 0.155 mol

Since, mol of malonic acid are least, so it would be the limiting reagent.

Theoratical yield of O2 = (mass of limiting reagent / molar mass of limiting reagent) x (stoichiometric coefficient of product ie O2/ stoichiometric coefficient of Limiting reagent) x molar mass of product ie O2

= (16.2 g / 104.06 gmol-1) x (2 / 1) x 32 gmol-1

= 9.92 g of O2 produced