In a 0.1 molar solution of NaCl in water,which one of the following will be closest to 0.1?
A)The mole fraction of NaCl.
B)The mass fraction of NaCl.
C)The mass percent of NaCl.
D)The molality of NaCl.
E)All of these are about 0.1.

Question

Quizplus · Accepted Answer

Molality is defined as the number of moles of solute per kilogram of solvent. In a 0.1 molar solution of NaCl in water, there is 0.1 mol of NaCl dissolved in 1 L of water. Assuming the density of water is 1 kg/L, the molality of NaCl is also 0.1 mol/kg. 
The mole fraction and mass fraction of NaCl depend not only on the concentration but also on the molecular weight of NaCl and the density of the solution. The mass percent only considers the mass of NaCl relative to the total mass of the solution, which is not necessarily the same as the concentration. Therefore, the molality of NaCl is the best choice to be closest to 0.1 in this case.

In a 01 Molar Solution of NaCl in Water,which One of the of the Following