141. Solving a chemistry problem

At a temperature of 25 ° C, a solution of iodine in water contains 5.16 * 10-5 mg / l of substance and is in equilibrium with a solution of iodine in CCl4 containing 4.41 * 10-3 mg / l. How many milliliters CCl4 must be taken in order to extract from 100 ml of an aqueous solution a) 90%, b) 99.9% of the dissolved iodine by one extraction. Answer: 10.5 ml, 1170 ml.