you have 10 mL of a 1.0 M Ba(OH)2 solution and add it to 2.5 L of water. What is the concentration of hydroxide ionsin the diluted Ba(OH)2 solution?

Answer 1

[Ba(OH)2] = 1.0M x (10/2500) = ??
(Or use mL x M = mL x M)
(OH)2 = twice that.