2L of 0.5 M H2SO4 are needed to exactly neutralize 3 liters of NaOH of an unknown concentration.

Question

2L of 0.5 M H2SO4 are needed to exactly neutralize 3 liters of NaOH of an unknown concentration. How do you find the concentration of the NaOH?

Answer 1

Hello, Robin,

The reaction follows this balanced equation:

H₂SO₄ + 2NaOH = Na₂SO₄ + 2H₂O

This tells us that it takes 1 mole of sulfuric acid to neutralize 2 moles of sodium hydroxide. If we can determine the moles H₂SO₄ required for neutralization, that number would be doubled to determine the moles NaOH.

Find the moles H₂SO₄ consumed by multiplying the 2L of H₂SO₄ times it's molarity, 0.5M, which is defined as 0.5 moles/liter.

(2L) * (0.5 moles/L) = 1 mole H₂SO₄

Multiply by 2 to find the moles NaOH. That means 2 moles NaOH were present in the 3 L of the solution.

Find the concentration by division:

2moles NaOH/3 L = 0.66 M

Bob