Calculate the molality of a 25.4% (by mass)aqueous solution of phosphoric acid (H₃PO₄). A)2.59 m B)3.47 m C)4.45 m D)25.4 m E)The density of the solution is needed to solve the problem.

Question

Quizplus · Accepted Answer

To calculate molality, we use the formula: molality (m) = moles of solute / kg of solvent. For a 25.4% solution, there are 25.4 g of H3PO4 in 100 g of solution. The moles of H3PO4 = 25.4 g / 98 g/mol = 0.259 moles. The mass of water (solvent) = 100 g - 25.4 g = 74.6 g = 0.0746 kg. Molality = 0.259 moles / 0.0746 kg = 3.47 m.

Calculate the Molality of a 25