Respuesta :
This method of quantitative determination of percent purity is titrimetric reactions. These reactions most commonly involve neutralization reactions between an acid and a base. Then, we look at the neutralization reaction:
H₂C₂O₄ + 2 NaOH ⇒ Na₂C₂O₄ + 2 H₂O
So, we do the stoichiometric calculations. The important data we should know is the molar mass of oxalic acid which is equal to 90 g/mol.
(0.2283 mol/L NaOH * 0.3798 L * 1 mol H₂C₂O₄/ 2mol NaOH * 90 g/mol H₂C₂O₄) ÷ 0.7984 g *100%
= 488%
This is impossible. The purity can't be more than 100%. Looking at our calculations and the balance reaction, all steps were done correctly. So, I think there is some typographical error in the given. The mass of the sample should be 7.984 g. Then, the answer would be 48.87% purity.
H₂C₂O₄ + 2 NaOH ⇒ Na₂C₂O₄ + 2 H₂O
So, we do the stoichiometric calculations. The important data we should know is the molar mass of oxalic acid which is equal to 90 g/mol.
(0.2283 mol/L NaOH * 0.3798 L * 1 mol H₂C₂O₄/ 2mol NaOH * 90 g/mol H₂C₂O₄) ÷ 0.7984 g *100%
= 488%
This is impossible. The purity can't be more than 100%. Looking at our calculations and the balance reaction, all steps were done correctly. So, I think there is some typographical error in the given. The mass of the sample should be 7.984 g. Then, the answer would be 48.87% purity.
Answer:
The percent of oxalic acid in a solid is 48.87%.
Explanation:
Mass of the solid sample = 0.7984 g
[tex]H_2C_4O_4+2NaOH\rightarrow Na_2C_2O_4+2H_2O[/tex]
Volume of NaOH solution = 37.98 mL = 0.03798 L
Concentration or molarity of the NaOH solution = 0.2283 M
Moles of NaOH :
[tex]Molarity\times \text{Volume of the solution} = 0.0086708 moles[/tex]
According to reaction, 2 moles of sodium hydroxide reacts with 1 mole of oxalic acid .
Then 0.0086708 moles of sodium hydroxide will react with:
[tex]\frac{1}{2}\times 0.0086708 moles=0.0043354 moles[/tex] of oxalic acid.
Mass of oxalic acid neutralized = 0.0043354 moles × 90 g/mol =0.390186 g
Percentage of oxalic acid in solid sample :
[tex]\%=\frac{\text{Mass of oxalic acid}}{\text{Mass of sample}}\times 100[/tex]
[tex]\%=\frac{0.390186 g}{0.7984 g}\times 100=48.87 \%[/tex]
The percent of oxalic acid in a solid is 48.87%.
