A capped flask contains solid in equilibrium with its saturated aqueous solution at…
CHEMISTRY · Single correct · AP · Chemistry · Equilibrium · Equilibrium
Problem
A capped flask contains solid CaF2 in equilibrium with its saturated aqueous solution at constant temperature. A small mass of NaF is added and dissolves. Which statement most accurately describes what subsequently occurs in the flask and why?
(a) No net change occurs; the added NaF simply increases ionic concentration without disturbing the Ksp of CaF2.
(b) Additional CaF2 dissolves because the higher ionic strength of the solution increases the salt’s solubility.
(c) Additional CaF2 precipitates because the rise in F− concentration shifts the dissolution equilibrium toward the solid until Q=Ksp again.
(d) The solution becomes basic as F− hydrolyzes to form OH−; the drop in F− concentration draws more CaF2 into solution.