ANSWER
The volume of acid used to neutralize the base is 19.43 mL
Step-by-step explanation
Given that;
The volume of Ba(OH)2 used is 20mL
The concentration of Ba(OH)2 is 0.328 M
The concentration of HCl used is 0.675M
To find the volume of HCl used, follow the steps below
Step 1; Write a balanced chemical equation for the reaction
In the above equation, 2 moles HCl react with 1 mole Ba(OH)2 to produced 1 mole BaCl2 and 2 moles H2O
Step 2; Write the acid-base titration formula
Where
CA is the concentration of the acid (HCl)
VA is the volume of the acid (HCl)
CB is the concentration of the base (Ba(OH)2
VB is the volume of the base is (Ba(OH)2
nA is the number of moles of acid
nB is the number of moles of base
Step 3; Substitute the given data into the formula in step 2
Hence, the volume of acid used to neutralize the base is 19.43 mL