A result of the common-ion effect is ________. A)that some ions, such as Na⁺(aq), frequently appear in solutions but do not participate in solubility equilibria B)that common ions, such as Na⁺(aq), don't affect equilibrium constants C)that the selective precipitation of a metal ion, such as Ag⁺, is promoted by the addition of an appropriate counterion (X^-)that produces a compound (AgX)with a very low solubility D)that ions such as K⁺ and Na⁺ are common ions, so that their values in equilibrium constant expressions are always 1.00 E)that common ions precipitate all counter-ions

Question

Quizplus · Accepted Answer

The common-ion effect occurs when the addition of an ion that is already present in a solution shifts the equilibrium of a reaction. In the case of selective precipitation, adding a counterion that forms a compound with a low solubility, such as AgX, can promote the precipitation of a metal ion, such as Ag+. This is because the addition of the common ion, in this case, X-, decreases the solubility of AgX and shifts the equilibrium towards precipitation. Therefore, choice C is the correct answer. Choices A, B, D, and E do not accurately describe the common-ion effect.

A Result of the Common-Ion Effect Is ________