How potassium iodide aids the titration of the cyclohexane layer.

to avoid iodine vapor from escaping.

Explanation:

This question is all about an experimental work on the determination of the distribution of iodine between waters and cyclohexane. To understand this question one has to understand the topic "Equilibrium" very well.

One important thing that must be noted in this question is for us to remember that water and cyclohexane are two immiscible liquids. So, when Iodine is added to the two solvents, the iodine dissolves in both water and cyclohexane to certain rate ands then to an equilibrium which is;

Kd = I₂[Cyclohexane]/ I₂[water]. [**].

There is a release of I⁻¹ From the added potassium iodide which helps in making sure that the iodine vapor does not escape. Thus, forming a tri-iodide ion.

the answer would be a