A solution is prepared containing 2 % sodium chloride (Na+Cl−). Which of the following best describes the osmolarity of this solution? (Note : Na = 23, Cl = 35.5)

B: 2 % = 2 g/100 ml = 20g/l. Mass of 1 mol of Na+Cl− = 23 + 35.5 = 58.5 g.

number of moles of Na+Cl− required for one litre of 2 % solution = 20 g/58.5 g

per mol = 0.34 mol. Sodium chloride is an ionic substance so dissociates into

ions when dissolved. This would produce 0.34 mol of Na and 0.34 mol of

Cl = 0.68 osmoles of dissolved particles in the one litre.

0.68 osmol/L = 680 mosmol/L