Question

To make a saturated solution, 15 g of sodium chloride is dissolved in 85 g of water at 293 K. Calculate the concentration in terms of mass by mass percentage at this temperature.
[2 Marks]

Answer 1

Given:
Mass of the solute (sodium chloride) = 15 g
Mass of the solvent (water) = 85 g

Mass of the solution = Mass of the solute + Mass of the solvent
= 15 + 85 = 100 g
Concentration (mass by mass percentage) = $\frac{\text{mass of solute}}{\text{mass of solution}}\times 100$
[1 Mark]
On putting values in the formula, we get
= $\frac{\text{15}}{\text{100}}\times 100$ = 15%
Hence, 15% is the concentration.
[1 Mark]