A typical vitamin C tablet (containing pure ascorbic acid, \(\mathrm{H}_{2} \mathrm{C}_{6} \mathrm{H}_{6} \mathrm{O}_{6}\) ) weighs \(500 . \mathrm{mg}\). One vitamin C tablet is dissolved in enough water to make \(200.0 \mathrm{~mL}\) of solution. Calculate the pH of this solution. Ascorbic acid is a diprotic acid.

The mass of ascorbic acid in the tablet is 500 mg. The molar mass of ascorbic acid is approximately 176.13 g/mol. To find the moles of ascorbic acid, we use the equation: \(\text{moles of ascorbic acid} = \frac{500\ \text{mg} \times \frac{1}{1000}\ \text{g/mg}}{176.13\ \text{g/mol}}\) Then, we find the concentration of ascorbic acid by dividing the moles of ascorbic acid by the volume of the solution (0.200 L): \(\text{concentration of ascorbic acid} = \frac{\text{moles of ascorbic acid}}{0.200\ \text{L}}\) Since ascorbic acid is diprotic, the concentration of H+ ions is twice the concentration of ascorbic acid. Finally, we can calculate the pH of the solution using the following formula: \(\text{pH} = -\log_{10}([\text{H}^{+}])\) Substitute the concentration of H+ into the pH formula to find the pH of the vitamin C solution.