Which of these statements about the common-ion effect is most correct? (a) The solubility of a salt MA is decreased in a solution that already contains either M+ or A-. (b) Common ions alter the equilibrium constant for the reaction of an ionic solid with water. (c) The common-ion effect does not apply to unusual ions like SO32 - . (d) The solubility of a salt MA is affected equally by the addition of either A- or a noncommon ion.

Video transcript

Hi everyone for this problem. It reads choose the most correct statement about the common ion effect. Okay, so the common ion effect is used to describe the effect on an equilibrium involving a substance that adds an ion that is part of the equilibrium. So let's take a look at our answer choices for a the common ion effect is not applicable. Unusual ions such as this one. Okay, so this is not going to be the most correct statement. Okay, because although it's an unusual ion, it's still applicable. Okay, so for b for a salt M. X, the addition of X. Or any other ion will affect the solid ability in the same way. So this is not the most correct statement because it's not going to affect the cell viability in the same way because X could be a common ion, it will affect it differently than any other ion. So that in the same way makes this statement incorrect statement. See the presence of M cat ion or X. And ions in the solution will decrease the solid ability of the salt, M. X. And that solution. Okay, so let's write this out. So we have assault. Okay and is that equilibrium? And these are our ions? Okay, so if we add or increase the concentration of either of the ions, this is going to make our equilibrium shift to the left which is going to have an effect on the solid ability of the salt, it's going to decrease the sala bility of the salt by shifting our equilibrium in that direction. Okay and so this is going to make answer choice C. Correct The presence of those ions in the solution will decrease the scalability of the salt mX. And that solution, let's go ahead and take a look at D. The addition of common ions will change the equilibrium constant for the dissociated for the dissolution of an ionic solid in water. Okay? So if we're adding common ions, this is going to change the number of moles, but not the concentration. Okay, so this is going to make this answer. Not the most correct statement. So out of the options given C is the most correct and that's the end of this problem. I hope this was helpful.