A student places 50.0 mL of 0.020 M Ca(NO ) in a beaker
CHEMISTRY · Single correct · AP · Chemistry · Equilibrium · Equilibrium
Problem
A student places 50.0 mL of 0.020 M Ca(NO3)2 in a beaker. She then adds 10.0 mL of 0.10 M NaF (Step 1) followed by an additional 40.0 mL of 0.10 M NaF (Step 2). For CaF2, Ksp=3.9×10−11. Which statement most accurately describes when precipitation of CaF2 occurs?
(a) A precipitate forms during Step 1 but redissolves completely after Step 2 due to dilution.
(b) Precipitation begins only after Step 2 because the fluoride concentration is too low after Step 1.
(c) All of the Ca2+ is removed as solid during Step 1, so the mixture is unaffected by the additional fluoride in Step 2.
(d) Precipitation begins during Step 1 and additional solid forms during Step 2.