If 32.8 mL of a 0.162 M NaOH solution is required to titrate 25.0 mL of a solution of H₂SO₄, what is the molarity of the H₂SO₄ solution?
H₂SO₄(aq) + 2 KOH(aq) → 2 H₂O(l) + K₂SO₄(aq)

Verified step by step guidance

1. Step 1: Write the balanced chemical equation for the reaction. The given equation is already balanced: H₂SO₄(aq) + 2NaOH(aq) → 2H₂O(l) + Na₂SO₄(aq). This shows that 1 mole of H₂SO₄ reacts with 2 moles of NaOH.
2. Step 2: Calculate the moles of NaOH used in the titration. Use the formula: moles = molarity × volume. Convert the volume of NaOH from mL to L by dividing by 1000, then multiply by the molarity (0.162 M).
3. Step 3: Use the stoichiometry of the reaction to determine the moles of H₂SO₄. From the balanced equation, 1 mole of H₂SO₄ reacts with 2 moles of NaOH. Divide the moles of NaOH by 2 to find the moles of H₂SO₄.
4. Step 4: Calculate the molarity of the H₂SO₄ solution. Use the formula: molarity = moles / volume. The volume of the H₂SO₄ solution is given as 25.0 mL, so convert it to liters by dividing by 1000, then divide the moles of H₂SO₄ by this volume.
5. Step 5: Double-check your units and calculations to ensure consistency and accuracy. The final molarity of the H₂SO₄ solution will be in units of moles per liter (M).

Key Concepts

Titration

Titration is a quantitative analytical technique used to determine the concentration of a solute in a solution. It involves the gradual addition of a titrant (a solution of known concentration) to a sample solution until the reaction reaches its endpoint, which is often indicated by a color change. In this case, NaOH is the titrant used to determine the molarity of H₂SO₄.

Stoichiometry

Stoichiometry is the calculation of reactants and products in chemical reactions based on the balanced chemical equation. It allows us to determine the relationships between the amounts of substances involved in the reaction. For the titration of H₂SO₄ with NaOH, the stoichiometric coefficients indicate that one mole of H₂SO₄ reacts with two moles of NaOH, which is crucial for calculating the molarity of the sulfuric acid solution.

Molarity

Molarity is a measure of concentration defined as the number of moles of solute per liter of solution. It is expressed in moles per liter (M). In this problem, the molarity of the H₂SO₄ solution can be calculated using the volume and molarity of the NaOH solution, along with the stoichiometric relationship from the balanced equation, to find the concentration of the sulfuric acid.