A solution of iodine in hydrocarbon solvent was shaken with water until equilibrium was reached. The mixture was allowed to settle and then 5 cm3 of the hydrocarbon solvent layer and 50 cm3 of the aqueous layer were removed and titrated separately with sodium thiosulfate solution of concentration 0.0100dm3. The hydrocarbon 5cm3 aliquot required 72.0 cm3 and the aqueous aliquot required 8.35 cm3 of the Na2SO3 (aq). The expression equilibrium constant kc for this equilibrium is [I2(hydrocarbon)]/[I2(aq)]. Calculate kc.