Calculate the molality of a 21.6% (by mass)aqueous solution of phosphoric acid (H₃PO₄). A)2.81 m B)276 m C)5.62 m D)1.41 m E)The density of the solution is needed to solve the problem.

Question

Quizplus · Accepted Answer

To calculate the molality of the solution, we need to determine the moles of solute (phosphoric acid) and the mass of solvent (water).

Let's assume we have 100 g of the solution. This means that we have:

- 21.6 g of phosphoric acid
- 78.4 g of water

To calculate the moles of phosphoric acid, we need to know its molar mass, which is:

- M(H3PO4) = 1x3 + 31 + 4x16 = 98 g/mol

The moles of phosphoric acid in the solution are:

- n(H3PO4) = m(H3PO4) / M(H3PO4) = 21.6 g / 98 g/mol = 0.22 mol

The mass of water in the solution is:

- m(H2O) = 78.4 g

The molality of the solution is:

- molality = n(H3PO4) / m(H2O) = 0.22 mol / 0.0784 kg = 2.81 m

Therefore, the answer is A) 2.81 m.

Calculate the Molality of a 21