A water sample contains 500 mg/L bicarbonate, 100 mg/L of carbonate ion, and has a pH of 9.5.What is the alkalinity of this water expressed as mg/L as CaCO3? Is

the pH measurement for the water accurate? Alkalinity is defined as: \text { Alk }(\mathrm{eq} / \mathrm{L})=\left[\mathrm{HCO}_{3}\right]+2\left[\mathrm{CO}_{3}^{2-}\right]+\left[\mathrm{OH}^{-}\right]-\left[\mathrm{H}^{+}\right]