Chapter 8, Problem 156AE

A student intends to titrate a solution of a weak monoprotic acid with a sodium hydroxide solution but reverses the two solutions and places the weak acid solution in the buret. After $\text{23}\text{.75 mL}$ of the weak acid solution has been added to $\text{50}\text{.00 mL}$ of the $\text{0}\text{.100 M NaOH}$ solution, the $\text{pH}$ of the resulting solution is $\text{10}\text{.50}$ . Calculate the original concentration of the solution of weak acid.