Acid-Base Titration Calculations

Question

• Example 1: 30 mL of 0.10 M NaOH neutralized 25.0
mL of hydrochloric acid. Determine the
concentration of the acid.

Answer 1

Step 1: Write out the balanced chemical equation for the reaction:
HCl + NaOH -> NaCl + H2O

Step 2: Calculate the number of moles of NaOH used:
n = M x V
n = 0.10 mol/L x 30 mL / 1000 mL/L
n = 0.003 mol

Step 3: Use the mole ratio from the balanced equation to determine the number of moles of HCl:
1 mol of NaOH neutralizes 1 mol of HCl
So, 0.003 mol of NaOH neutralizes 0.003 mol of HCl

Step 4: Calculate the concentration of HCl:
C = n / V
C = 0.003 mol / 25.0 mL / 1000 mL/L
C = 0.12 mol/L

Therefore, the concentration of the hydrochloric acid is 0.12 M.