When 200. mL of water are added to 100. mL of 12% KCl solution the final concentration of KCl is?

Question

Assume the volumes add.

Answer 1

There are a couple of ways to solve this problem.

(1)  (100 ml)(12%) = (300 ml)(x %) and x = 4%

(2)  100 ml x 12g/100 ml = 12 g of KCl

12 g KCl/300 ml = 0.04 g KCl/ml = 4%