Question

If 6.5 L of water is added to 4.5 L of a 2.8 M Ca(OH)2 solution, what is the molarity of the new solution?

Answer 1

Find moles of Ca(OH)2 first:

moles = 2.8 x 4.5 = 12.6

Now,
   After addition, new volume =  6.5 + 4.5 = 11.0

So, new molarity =  12.6 / 11 = 1.145