A student dilutes a solution of 0.100 mol of H3PO4 and 0.150 mol of NaOH with water to a volume of 1.00 L but then realizes that the "distilled water" used was in fact dilute hydrochloric acid.
a)If the pH of the final solution is 6.50, what are the concentrations of H3PO4, H2PO4^-, and HPO4^2-?
b)How many moles of HCl were inadvertently added to the original solution?