Determination of the rate of reaction between potassium iodide and potassium peroxodisulphate with the econoburette: a green chemistry and microscale titrations

Measurement for a rate of reaction for about 30 min at a 5 min interval between KI and K2S2O8 aqueous solutions with conventional burette in industries and academics consumes about 3.375 g K2S2O8/250 mL : 4.15 g KI/250 mL : 11.6 mL (CH3COOH, glacial)/100 mL : 1 g starch/10 mL : 0.62 g Na2S2O3 (sodium thiosulphate)/250 mL : 50 mL ice cold water. The number after the oblique in mL depicts an amount of aqueous solution where the amounts of chemicals in grams are dissolved. Similar determinations with econoburette reduced their amounts in 0.0675 g K2S2O8/5 mL : 0.083 g KI/5 mL: 0.5 mL (CH3COOH, glacial)/5 mL : 0.05 g starch/0.5 mL : 0.025 g Na2S2O3/2 mL : 2.5 mL ice cold water. The reduction in amounts is about 50 times, and similarly the time and operational efforts are reduced in the same proportion. The econoburette is a 'green chemistry' instrument which performs valuable titration with microlitre of substances. The micro level amount of titer and titrant consumed less time in performing a volumetric tititration and also prevented much use of materials. In general, after titration a significant quantity of indicators, additives, titer and titrant are consumed and drained out in a sink with the possibility of causing pollution. The econoburette reduces such wastage of materials by up to 90%, with high accuracy in results. The rate constant k = 0.0431 sec-1 L-1 mol-1 remained fairly constant for successive measurements with time but with the conventional burette larger deviations were noted at 298.15 Kelvin temperature.