Question

You have 26.7 mL of 0.061 mol/L aqueous potassium hydroxide (KOH(aq)) in a conical flask. In a burette

you have 0.086 mol/L H2SO4(aq). If you titrate the two solutions, what volume (mL) of the H2SO4 solution
is required to reach the equivalence point (endpoint)?

Answer 1

9.47 mL

Step-by-step explanation:

The reaction that takes place is:

• 2KOH + H₂SO₄ → K₂SO₄ + 2H₂O

First we calculate how many KOH moles reacted, using the given concentration and volume of KOH solution:

• 0.061 mol/L = 0.061 mmol/mL

• 0.061 mmol/mL * 26.7 mL = 1.6287 mmol KOH

Then we convert KOH moles into H₂SO₄ moles, using the stoichiometric coefficients:

• 1.6287 mmol KOH *
  `(1mmolH_2SO_4)/(2mmolKOH)` = 0.8144 mmol H₂SO₄

Finally we calculate the required volume of the H₂SO₄ solution, using the number of moles and given concentration:

• 0.8144 mmol ÷ 0.086 mmol/mL = 9.47 mL