Question

Volume of distilled water used 12.09 mL
Volume of HCl added 0.87 mL
Concentration of added HCl 1.979 M

pH of diluted HCl solution ___________________

Answer 1

HCl is a strong acid, so the pH=-log[Molarity of HCl]


Calculate the molarity of HCl

Molarity of HCl=[(0.87mL)*(1.979)]/12.96mL]

Plug in the numbers and solve.