To determine the normality of a solution, we need to know the number of acid or base equivalents present in one liter of the solution. In the case of phosphoric acid (H3PO4), it can donate three protons (H+) per molecule.
The molarity (M) of the solution is given as 0.0521 M, which means there are 0.0521 moles of H3PO4 per liter of solution.
Since phosphoric acid donates three protons per molecule, the number of acid equivalents in one liter of the solution is three times the number of moles of H3PO4. Therefore:
Number of acid equivalents = 3 × (0.0521 moles) = 0.1563 equivalents
The normality (N) of a solution is defined as the number of acid or base equivalents per liter of solution. So, the normality of the 0.0521 M H3PO4 solution is 0.1563 N.