Question

You evaporate all of the water from 100 mL of NaCl solution and obtain 11.3 grams of NaCl. What was the molarity of the NaCl solution?

Answer 1

Answer:

                      Molarity  =  1.93 mol.L⁻¹

Explanation:

             Molarity is the unit of concentration used to specify the amount of solute in given amount of solution. It is expressed as,

                         Molarity  =  Moles / Volume of Solution    ----- (1)

Data Given;

                  Mass  =  11.3 g

                  Volume  =  100 mL  =  0.10 L

First calculate Moles for given mass as,

                   Moles  =  Mass / M.mass

                   Moles  =  11.3 g / 58.44 g.mol⁻¹

                   Moles  =  0.1933 mol

Now, putting value of Moles and Volume in eq. 1,

                        Molarity  =  0.1933 mol ÷ 0.10 L

                        Molarity  =  1.93 mol.L⁻¹