Question

The molarity of a solution that contains 28 g KOH (molar mass 56 g/mol) per 250 mL of solution is:

Answer 1

Molarity = moles of solute/volume of solution in liters

The solute here is KOH. We have the mass of KOH, and we can calculate the number of moles by dividing by the molar mass: (28 g KOH)/(56 g/mol) = 0.5 mol KOH. The volume of our solution is 0.250 L.

So, the molarity of the solution would be (0.5 mol KOH)/(0.250 L) = 2 mol/L KOH or 2 M KOH.