Final answer:
When extracted with 6 M HCl, a basic compound A would form a water-soluble salt and dissolve in the aqueous layer, while a neutral compound B would remain in the ethyl acetate layer, effectively becoming more concentrated in that layer.
Step-by-step explanation:
When a solution containing compounds A and B in ethyl acetate is extracted with 6 M HCl, we must consider the properties of A and B when exposed to an acidic environment. Generally, if a compound has basic properties or is an amine, it will react with HCl to form a water-soluble salt, thereby migrating into the aqueous phase. If compound A is a base and compound B is neutral or non-basic, then upon extraction with 6 M HCl, compound A will dissolve in HCl forming a chloride salt and compound B will remain in the ethyl acetate layer, becoming more concentrated. Therefore, it seems likely that the correct answer would be D) Compound A will become more soluble in ethyl acetate. However, without specific information on the properties of A and B, this is a tentative conclusion.