[ocojam]

In a separating funnel there are these two layers

Top layer: iodine dissolved in cyclohexane
Bottom layer: iodine in water

If I add CCl4 to the solution and shake, which layer changes colour first?

[Burner]

Hint: Which layer of liquid will iodine be most readily dissolve in?

[ocojam]

The cyclohexane, so that is already purple and the bottom layer should be clear at the start. But will the bottom layer still have some of the iodine in it? and I don't know what will happen when the CCl4 is added

[AWK]

This is a problem. Carbon tetrachloride is miscible with cyclohexane. For mole fraction of CCl₄ greater then 0.33 density of the carbon tetrachloride-cyclohexane solution is greater then that of water. Hence violet solution may be in upper layer or in bottom layer depending on amount of carbon tetrachloride added.

[Burner]

Molar mass of CCl₄: 153.81 g mol^-1
Molar mass of I₂: 253.80894 g mol^-1
Molar mass of cyclohexane: 84.16 g mol^-1

I think CCl₄ should be most soluble in CCl₄(Intermolecular forces of CCl₄ and I₂ are more comparable because of closer molar mass). But as @AWK said, CCl₄ and cyclohexane are miscible, so I₂ may dissolve in the 'mixture' of them.