volume of NaOH = 54 mL / 1000 = 0.054 L
Molarity NaOH = 0.1 M
Number of moles NaOH :
n = M * v
n = 0.1 * 0.054
n = 0.0054 moles of NaOH
Finally we calculate the number of moles of HCl in the solution from the stoichiometry of the reaction :
HCl + NaOH = NaCl + H₂O
1 mole HCl -------- 1 mole NaOH
? moles HCl ------- 0.0054 moles NaOH
moles HCl = 0.0054 * 1 /1
= 0.0054 moles of HCl
Volume of HCl = 125 mL / 1000 = 0.125 L
M ( HCl ) = n / V
M = 0.0054 / 0.125
= 0.0432 M
hope this helps!
