Answer:
0.8764 M
Explanation:
Equation of the reaction:
NaOH + HCl --> NaCl + H2O
Number of moles = molar concentration × volume
= 0.039 × 0.639
= 0.0252 mol
By stoichiometry, 1 mole of HCl reacted with 1 mole of NaOH. Therefore, number of moles of HCl = 0.0252 mol
Molar concentration of HCl = number of moles ÷ volume
= 0.0252 ÷ 0.0288
= 0.8764 M of HCl.
