We’re being asked to calculate the molarity (M) of a solution of NaI. Recall that molarity is the ratio of the moles of solute and the volume of solution (in liters). In other words:
We first need to determine the number of moles of NaI since this is the only information missing for us to find molarity. Notice that the volume of the solution in liters is already given.
We’re given the mass of NaI, 10.7 g. We can use the molar mass of NaI to find the moles. The molar mass of NaI is
The moles of NaI is:
We know that the volume of the solution is 0.250 L. We can now calculate for molarity:
What is the molarity of a solution prepared by dissolving 10.7 g Nal in 0.250 L?
C) 2.86 x 10-4
E) none of the above