Question

If 25.0 mL of 0.451 M NaOH solution is titrated with 0.253 M H2SO4, the flask at the endpoint will contain (besides the indicator phenolphthalein) as the principal components:

Answer 1

H₂O, Na⁺, and SO₄²⁻

Step-by-step explanation:

NaOH and H₂SO₄ are strong electrolytes. They will ionize completely .

Molecular equation: 2NaOH + H₂SO₄ ⟶ Na₂SO₄ + 2H₂O

Ionic equation: 2Na⁺ + 2OH⁻ + 2H⁺ + SO₄²⁻ ⟶ 2Na⁺ + SO₄²⁻+ 2H₂O

• The concentration of water is 55.5 mol·L⁻¹.
• The concentration of Na⁺ is twice that of SO₄²⁻ .
• Hydrolysis of SO₄²⁻ is negligible.

The principal components in the flask at the endpoint are H₂O, Na⁺, and SO₄²⁻.