Answer:
12.5 mL of HCl
Explanation:
The balanced chemical equation for the neutralization reaction is as follows
NaOH + HCl —> NaCl + H2O
Molar ratio of NaOH to HCl is 1:1
For neutralization to happen the number of NaOH moles is equal to the number of HCl moles
Number of NaOH moles reacted - 0.20 mol/L x 0.025 L = 0.005 mol
Therefore number of HCl moles reacted - 0.005 mol
Concentration of HCl is 0.40 mol/L
Concentration = number of moles / volume
Rearranging the equation
Volume = number of moles / concentration
Volume = 0.005 mol / 0.40 mol/L
= 0.0125 L
Volume of HCl added is 12.5 mL
