Unlocking the Power of Phosphoric Acid Solutions

How can we determine the molality of a solution containing phosphoric acid and water?

Given: 24.5 g of phosphoric acid in 100 g of H₂O

Molality Calculation:

The molality of the solution can be calculated using the formula:

molality (m) = moles of solute / mass of solvent (kg)

Exploring the Solution's Molality:

To find the molality of the solution containing phosphoric acid, we start by converting the mass of phosphoric acid to moles using the molar mass of H3PO4, which is 98 g/mol.

moles of H3PO4 = 24.5 g H3PO4 × (1 mol H3PO4 / 98 g H3PO4) = 0.25 mol H3PO4

Next, we convert the mass of water to kilograms:

mass of H2O = 100 g H2O × (1 kg / 1000 g) = 0.1 kg H2O

Finally, we substitute the values into the formula:

molality = 0.25 mol H3PO4 / 0.1 kg H2O = 2.5 mol/kg

This calculation reveals that the molality of the solution of phosphoric acid in water is 2.5 mol/kg, unlocking the true potential of this powerful solution.