Acid-Base Titration Calculations

Question

• Example 2: A titration of 50.00 mL of an unknown
concentration of H2SO4 with standardized base
required 25.00 mL of 0.1000 M NaOH. What is the
unknown concentration of H2SO4?

Answer 1

First, write the balanced chemical equation for the reaction:

H2SO4 + 2NaOH -> Na2SO4 + 2H2O

From the equation, we can see that the mole ratio between H2SO4 and NaOH is 1:2.

Next, calculate the moles of NaOH used in the titration:

moles of NaOH = Molarity x Volume
moles of NaOH = 0.1000 mol/L x 0.02500 L
moles of NaOH = 0.00250 mol

Since the mole ratio between H2SO4 and NaOH is 1:2, we know that the moles of H2SO4 present in the solution is half of the moles of NaOH used in the titration.

moles of H2SO4 = 0.00250 mol / 2
moles of H2SO4 = 0.00125 mol

Now, calculate the concentration of H2SO4 in the original solution:

concentration of H2SO4 = moles of H2SO4 / volume of H2SO4 solution
concentration of H2SO4 = 0.00125 mol / 0.05000 L
concentration of H2SO4 = 0.0250 M

Therefore, the unknown concentration of H2SO4 is 0.0250 M.