To calculate the molarity of a solution, you need to use the formula:
Molarity (M) = Number of moles of solute / Volume of solution (in liters)
a) In this case, we are given the number of moles of KCl as 1.0 mol and the volume of the solution as 750 mL. However, the formula requires the volume to be in liters. So we need to convert 750 mL to liters.
750 mL = 750 mL * (1 L / 1000 mL) = 0.75 L
Now, we can substitute the values into the formula to find the molarity:
Molarity (KCl) = 1.0 mol / 0.75 L = 1.33 M
So, the molarity of the KCl solution is 1.33 M.
b) Similarly, for the second solution, we are given the number of moles of MgCl2 as 0.50 mol and the volume of the solution as 1.5 L.
Molarity (MgCl2) = 0.50 mol / 1.5 L = 0.33 M
Therefore, the molarity of the MgCl2 solution is 0.33 M.