Question

What is the molarity of a NaOH solution if 28.2 mL of a 0.355 M H2SO4 solution is required to neutralize a 25.0-mL sample of the NaOH solution?A) 0.801B) 0.315C) 0.629D) 125E) 0.400

Answer 1

Answer:

A) 0.801

Explanation:

The reaction that takes place is:

• 2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O

First we calculate the H₂SO₄ moles that reacted:

• 0.355 M * 28.2 mL = 10.011 mmol H₂SO₄

Now we convert H₂SO₄ moles to NaOH moles:

• 10.011 mmol H₂SO₄ * $\frac{2mmolNaOH}{1mmolH_2SO_4}$ = 20.022 mmol NaOH

Finally we calculate the molarity of the NaOH solution:

• 20.022 mmol NaOH / 25.0 mL = 0.801 M

So the answer is option A.