Question

when carrying out an extraction, which of the following maximises the yield of extracted product from 25ml of solution, using 1 x 75ml or doing 3 successive extractions of 25ml each. explain your reasoning.

Answer 1

To maximize yield from a 25ml solution, 3 successive extractions of 25ml each are more effective than a single 75ml extraction due to the principle of the partition coefficient, as more of the solute is moved into the extracting phase through multiple partitions.

Step-by-step explanation:

When carrying out an extraction, to maximize the yield of extracted product from a 25ml solution, performing 3 successive extractions of 25ml each is generally more effective than using a single 75ml extraction. The reasoning behind this is based on the principle of partition coefficient or distribution coefficient, which is the ratio of concentrations of a compound in the two phases of a mixture of two immiscible solvents at equilibrium. Given a fixed amount of substance to be extracted and a fixed total volume of extracting solvent, multiple extractions with smaller volumes of solvent can move more of the solute from the original phase into the extracting phase than a single extraction, due to the compound being partitioned at each step.

In mathematical terms, given the partition coefficient (K), you can calculate the amount remaining in the original solution after multiple extractions using the formula: remaining amount = initial amount × (1/(1+K))^n, where n is the number of extractions. Therefore, as n increases, the amount remaining decreases, thus increasing the overall yield of extracted material.