Concentration Calculation in Acid-Base Titration

In a biochemical laboratory, a researcher is performing a titration experiment to determine the concentration of an unknown hydrochloric acid (HCl) solution. The researcher uses a standard sodium hydroxide (NaOH) solution of known concentration at 0.1 M. During the titration, the researcher records that the endpoint occurs when 25 mL of the NaOH solution is added to 50 mL of the HCl solution.

Given that the reaction between HCl and NaOH is a strong acid-strong base neutralization, what is the concentration of the unknown HCl solution in moles per liter (M)?