Questions: A titration of 47.1 mL of a sulfuric acid (H₂SO₄) solution of unknown concentration with a standardized 1.55 M Ba(OH)₂ solution required 23.0 mL to reach the second equivalence point. What is the concentration of the H₂SO₄ solution?

Solution Steps

The balanced chemical equation for the reaction between sulfuric acid (H₂SO₄) and barium hydroxide (Ba(OH)₂) is:

\[ \text{H}_2\text{SO}_4 + \text{Ba(OH)}_2 \rightarrow \text{BaSO}_4 + 2\text{H}_2\text{O} \]

This equation shows that one mole of H₂SO₄ reacts with one mole of Ba(OH)₂.

The concentration of Ba(OH)₂ is given as 1.55 M, and the volume used is 23.0 mL. First, convert the volume from milliliters to liters:

\[ 23.0 \, \text{mL} = 0.0230 \, \text{L} \]

Now, calculate the moles of Ba(OH)₂:

\[ \text{Moles of Ba(OH)}_2 = 1.55 \, \text{mol/L} \times 0.0230 \, \text{L} = 0.03565 \, \text{mol} \]

From the balanced equation, we know that the mole ratio of H₂SO₄ to Ba(OH)₂ is 1:1. Therefore, the moles of H₂SO₄ are equal to the moles of Ba(OH)₂:

\[ \text{Moles of H}_2\text{SO}_4 = 0.03565 \, \text{mol} \]

The volume of the H₂SO₄ solution is 47.1 mL, which needs to be converted to liters:

\[ 47.1 \, \text{mL} = 0.0471 \, \text{L} \]

Now, calculate the concentration of H₂SO₄:

\[ \text{Concentration of H}_2\text{SO}_4 = \frac{0.03565 \, \text{mol}}{0.0471 \, \text{L}} = 0.7567 \, \text{M} \]

Final Answer