What is the molarity of a bleach solution containing 5.8 g of NaOCl per liter of bleach?

Question

What is the molarity of a bleach solution containing 5.8 g of NaOCl per liter of bleach?

Answer 1

Molarity refers to moles of a substance per liter of solution. We must first convert our 5.8g of NaOCl to moles in order to determine the molarity (M):

5.8g NaOCl x (1 mol NaOCl / 74.44 g NaOCl) = 0.07791509941 mol NaOCl ~ 0.078 mol NaOCl with significant digits

This was done using the molar mass of NaOCl, 74.44 g / mol, in order to obtain the moles of NaOCl from the grams of NaOCl. When the mass is divided by the molar mass, the grams cancel out to give units in only moles which is what we are looking for. Next, we must divide the moles of NaOCl by the liters of the solution to obtain molarity (M). The problem states that there are 5.8 g NaOCl per liter of bleach which gives us the following:

5.8 g NaOCl / L bleach = 0.078 mol NaOCl / L bleach = 0.078 M

The molarity of our solution is 0.078 M (M = mol / L)