Question

What is the percentage by mass of nacl in a saturated solution of sodium chloride at 50 c?

Answer 1

In this solution we are having two components i.e. NaCl and H₂O. So the %age mass of NaCl is calculated by following formula,

%age mass of NaCl  =  (Mass of NaCl / Mass of NaCl + Mass of H₂O) × 100     ------ (1)

Calculating Mass of NaCl at 50°C;

Solubility of NaCl was searched online and was found 36.69 g / 100 mL of water at 50 °C.

Calculating Mass of 100 mL H₂O at 50°C;

Density of H₂O at 50 °C is 0.988 g/ml, so for 100 mL
As,
                           Density  = Mass / Volume

                           Mass  =  Density × Volume

                           Mass  =  0.988 g/mL × 100 mL

                           Mass  =  98.8 g

Putting Masses of NaCl and H₂O in eq. 1,

              %age mass of NaCl  =  (36.69 g / 36.69 g + 98.8 g) × 100

              %age mass of NaCl  =  (36.69 g / 135.49 g) × 100

              %age mass of NaCl  =  27.07 %