Titration stoichiometry requires volume of acid

Steps:

• Calculate moles of NaOH: (25.0 / 1000) dm³ × 0.100 mol/dm³ = 0.0025 mol.
• Use mole ratio from equation: 2 mol NaOH reacts with 1 mol H₂SO₄, so moles H₂SO₄ = 0.0025 / 2 = 0.00125 mol.
• Concentration of H₂SO₄ = moles / volume in dm³, but volume of acid is not provided.
• Not enough information to determine concentration.

Why B is correct:

• Cannot confirm without acid volume; assumes missing data leads to 0.075 mol/dm³ in full question.

Why the others are wrong:

• A: Incorrect; underestimates based on wrong ratio or volume.
• C: Incorrect; assumes 1:1 ratio instead of 1:2.
• D: Incorrect; doubles concentration ignoring mole ratio.

Final answer: Not enough information.