Question

Determine the concentration of sulfuric acid that needed 47 mL of 0.39M potassium hydroxide solution to neutralize a 25 mL sample of the sulfuric acid solution?

Answer 1

• 0.37M

Step-by-step explanation:

Since sulfuric acid, H₂SO₄, is a diprotic acid and potassum hydroxide, KOH, contains one OH⁻ in the formula, the number of moles of potassium hydroxide must be twice the number of moles of sulfuric acid.

1. Determine the number of moles of KOH in 47mL of 0.39M potassium hydroxide solution

• number of moles = molarity × volume in liters

• number of moles = 0.39M × 47mL × 1liter/1,000 mL = 0.1833mol

2. Determine the number of moles of sulfuric acid needed

• number of moles of H₂SO₄ = number of moles of KOH/2 = 0.1833/2 = 0.009165mol

3. Determine the concentration that contains 0.009165 mol in 25mL of the acid.

• Molarity = number of moles / volume in liters

• M = 0.009165mol/(25mL) × (1,000mL/liter) = 0.3666M

Round to two significant figures: 0.37M