Question

When 20.0 g of sodium fluoride is dissolved in water to prepare the total volume of 200.0 mL solution, what is the molarity of the solution?

Answer 1

The molarity of the solution is 2.38 mol/L

Explanation:

Since molar concentration (molarity) is defined as moles of solute per litre of solution, we will first have to convert the mass of the NaF (molar mass = 42 g) into moles:

moles NaF = `(20.0 g) / (42 g/"mol") = 0.476` mol

Now, we divide:

Molarity = ("moles of solute")/("litres of solution")

#= 0.476 "mol"/ 0.200 L = 2.38 mol/L