the balanced equation for the acid base reaction is as follows
NaOH + HCl ---> NaCl + H₂O
stoichiometry of NaOH to HCl is 1:1
the number of NaOH moles is - 0.139 mol/L x 0.0154 L = 0.00214 mol
the number of NaOH moles reacted = number of HCl moles reacted
therefore number of HCl moles reacted = 0.00214 mol
volume of HCl containing 0.00214 mol - 25.0 mL
number of HCl moles in 25.0 mL - 0.00214 mol
therefore number of HCl moles in 1000 mL - 0.00214 mol / 25.0 mL x 1000 mL/L
molarity of HCl is 0.0856 mol/L
concentration of HCl is 0.0856 M
