If 80 mL of 0.050 M EDTA is added to 50 mL of 0.100 M metal ions, what is the concentration of free-floating metal ions before the equivalence point?

• A. 7.69 x 10^-3 M
• B. 2.50 x 10^-3 M
• C. 5.00 x 10^-3 M
• D. 1.00 x 10^-2 M

Answer: (A)