If sodium sulfate was added to the mixture containing silver ions and the yellow precipitate, what might be observed after a significant amount of time elapsed?

Very little to no formation of silver sulfate, as the silver sulfate Ksp (solubility product) is very large compared to the yellow precipitate Ksp.

By adding sodium sulfate to the silver / yellow precipitate mix, this question asks us to find a potential result and justification for the outcome. This implies that we will have to select the right answer that has a valid result and an adequate explanation for it. A substance's Ksp, or solubility product, is defined as the product of the dissolved ion concentration of each substance elevated to the power of its stoichiometric coefficient.