Chapter 9, Problem 9.97E

A $\text{25}\text{.00-mL}$ sample of gastric juice is titrated with a $0.0210\text{M}\text{NaOH}$ solution. The titration to the equivalence point requires $\text{26}\text{.4}\text{mL}$ of $\text{NaOH}$ solution. If the equation for the reaction is

$\text{HCl}\left(\text{aq}\right)+\text{NaOH}\left(\text{aq}\right)\to \text{NaCl}\left(\text{aq}\right)+{\text{H}}_{\text{2}}\text{O}\left(l\right)$

what is the molarity of $\text{HCl}$ in the gastric juice?