High School

A chemistry student needs to standardize a fresh solution of sodium hydroxide. He carefully weighs out 86 mg of oxalic acid ([tex]H_2C_2O_4[/tex]), a diprotic acid that can be purchased inexpensively in high purity, and dissolves it in 250 mL of distilled water. The student then titrates the oxalic acid solution with his sodium hydroxide solution. When the titration reaches the equivalence point, the student finds he has used 97.6 mL of sodium hydroxide solution. Calculate the molarity of the student's sodium hydroxide solution.

Answer :

The molarity of the student's sodium hydroxide solution is approximately **0.00976 M**.

The balanced chemical equation for the reaction between sodium hydroxide (NaOH) and oxalic acid (H₂C₂O₄) is:

[tex]\(2 \, \text{NaOH} + \text{H₂C₂O₄} \rightarrow \text{Na₂C₂O₄} + 2 \, \text{H₂O}\)[/tex]

From the equation, you can see that 2 moles of sodium hydroxide react with 1 mole of oxalic acid.

Given the volume of sodium hydroxide solution used (97.6 mL) and the mass of oxalic acid (86 mg), we can first calculate the number of moles of oxalic acid:

Number of moles of oxalic acid = [tex]\(\frac{\text{mass}}{\text{molar mass}}\)Molar mass of oxalic acid (H₂C₂O₄) = \(2 \times \text{atomic mass of H} + 2 \times \text{atomic mass of C} + 4 \times \text{atomic mass of O} = 2 \times 1.01 + 2 \times 12.01 + 4 \times 16.00 = 90.04 \, \text{g/mol}\)Number of moles of oxalic acid = \(\frac{0.086 \, \text{g}}{90.04 \, \text{g/mol}} = 0.000955 \, \text{mol}\)Since 2 moles of NaOH react with 1 mole of H₂C₂O₄, the number of moles of NaOH used is also \(0.000955 \, \text{mol}\).[/tex]

Now we can calculate the molarity of the sodium hydroxide solution:

Molarity (M) = [tex]\(\frac{\text{moles of solute}}{\text{volume of solution (L)}}\)Volume of solution (L) = \(97.6 \, \text{mL} = 0.0976 \, \text{L}\)[/tex]

Molarity = [tex]\(\frac{0.000955 \, \text{mol}}{0.0976 \, \text{L}} = 0.00976 \, \text{M}\)[/tex]

**Summary:** The molarity of the student's sodium hydroxide solution is approximately **0.00976 M**.

To know more about molarity refer here:
https://brainly.com/question/31545539#

#SPJ11

Other Questions