Question

HgBr2, has a solubility of 0.50 g HgBr2/100.0 g H2O at 20°C. If the solution is saturated at

this temperature, calculate the molality of the solution.

Answer 1

Mass of HgBr2= 0.50g

Molecular mass of HgBr2= 360.41 g/mol

Mass of solvent (H2O)= 100g

Temperature =20°C= 293K

We know that Molality is a property of a solution and is defined as the number of moles of solute per kilogram of solvent. The SI unit for molality is mol/kg.

Molality = (mass of solute × 1000)/(molecular mass of solute × mass of solvent )

Molality = (0.5g× 1000)/(360.41 g/mol × 100)

Molality= 0.0138 mol/kg

The molality of the solution is 0.0138m.