Given:
Volume of Ba(NO3)2 solution = 25.0mL Concentration of Ba(NO3)2 solution = 0.050M Volume of NaF solution = 25.0mL Concentration of NaF solution = 0.020M
[Ba+2]=(5025×0.05)=0.025M
[F−]=(5025×0.02)=0.01M
[Ba+2] [F−]=25×10−7
Ksp=0.5×10−6=5×10−7
Ratio=Ksp[Ba+2][F−]=5×10−725×10−7=5