I\'m currently doing a lab in Analytical Chemistry, \'Analysis of Vitamin C by I

Question

I'm currently doing a lab in Analytical Chemistry, 'Analysis of Vitamin C by Iodimetric Titration' and in order to make a Sodium Thiosulfate solution, I had to boil water before hand. I was wondering why boiling the water was necessary and also what balanced reaction could occur that would reduce the concentration of sodium thiosulfate if I didn't boil the water in the solution?

Explanation / Answer

The water must be boiled to remove traces of dissolved carbon dioxide (CO2). CO2 dissolves in water to form carbonic acid (H2CO3): CO2 + H2O => H2CO3 H2CO3 is a weak acid and partially ionizes to give H+ ions: H2CO3 => H+ + HCO3- HCO3- => H+ + CO32- The H+ ions can decompose thiosulfate ions and reduce the concentration of sodium thiosulfate according to the reaction: 2 S2O32- + H+ => HSO3- + S

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.