Complete and balance the following redox equations I^-(aq) + O_3(g) + H^+ (aq) r

Question

Complete and balance the following redox equations I^-(aq) + O_3(g) + H^+ (aq) rightarrow IO_3^-(aq) + I^- (aq) + OH^-(aq) rightarrow Is the thiosulfate ion, CIO an oxidizing or reducing agent? How many elections are transferred in reaction (1a)? In the standardization process, when the iodate-iodide solution is acidified with H_2SO_4, it should be titrated immediately. Why? What is the color of the iodate-iodide solution being titrated with Na_2S_2O)3 before the starch solution is added? after the starch solution is added? at the end point? If 18.92 mL of a Na_2S_2O_3 solution were required to titrated the iodine formed from 20.95 mL of a 0.0111 M KIO_3 solution and excess KI, what is the molarity of the Na_2S_2O_3 solution? A sample of bleach weighing 2.085 g was treated with an excess of KI. The iodine liberated required 30.21 mL of the Na_2S_2O_3 solution standardized in the previous question. Calculate the percent NaOCl in the bleach. Identify the two standard solutions used in this experiment in this experiment.

Explanation / Answer

Pre-lab

1. Balancing the equation,

(a) 2I-(aq) + 2O3(g) + 2H+(aq) ---> 2O2 + I2 + H2O

(b) IO3-(aq) + 5I-(aq) + 3H2O(l) ---> 3I2(s) + 6OH-(aq)

2. ClO- is an oxidizing agent

3. In 1a 2 e- are transferred

4. The I2 is formed immediately and should be titrated as shown as formed or it forms I3- complex in solution.

5. a. the color of iodate-iodide is light yellow.

b. blue black after startch is added (could be like purple as well)

c. the color shifts to colorless at the end point.

6. moles of KIO3 = 0.0111 M x 20.95 ml = 0.2325 mmol

moles of I2 formed = 3 x 0.2325 = 0.700 mmol

moles of Na2S2O3 required = 2 x 0.7 = 1.4 mmol

Molarity of Na2S2O3 = 1.4 mmol/18.92 ml = 0.074 M

7. moles of Na2S2O3 used = 0.074 M x 30.21 ml = 2.23554 mmol

moles of NaOCl = 2.23554/2 = 1.11777 mmol

mass of NaOCl = 1.11777 x 74.44/1000 = 0.0832 g

percent NaOCl = 0.0832 x 100/2.085 = 3.99%

8. Standard solutions used in the experiment are KIO3 solution and H2O2 solution

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---

---

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