Production Of Sinc Iodide

Determining the Most Cost Efficient Production of Zinc Iodide

Introduction. In the experiment Zinc Iodide was produced from raw Zinc and Iodine. The reaction between the two was performed on a small scale in a test tube forming Zinc Iodide solid. Once the solid was formed and dried it was weighed to determine the final mass of product. Using the measurements along with the prices of raw Zinc and Iodine, calculations were performed to determine the limiting reagent of the reaction and the most cost efficient way to produce 1000 kg of Zinc Iodide (ZnI2).

Experimental Procedure. At the beginning of the experiment the reactants were gathered. On an analytical balance approximately 0.5g zinc metal and 0.5g iodine crystals were weighed and brought to the lab bench. Next a 10 mL solution of 0.20 M acetic acid had to be made from 1.0 M acetic using the calculations from the formula: (M1)(V1) = (M2)(V2). In a test tube the samples of Iodine and Zinc along with 1 mL of the 0.20 M acetic acid solution were then combined. After shaking the test tube for a few minutes the reaction was complete and the liquid product was decanted into a second test tube containing 3 boiling chips. The remaining product in the first test tube was then washed twice more and the liquid product was again decanted into the second test tube. The solution in this test tube was then dried over a Bunsen burner to reveal a white solid precipitate. This test tube was then weighed on the analytical balance with the solid precipitate in it. The reaction that occurred in the experiment to form Zinc Iodide was Zn(s) + I2(s)ЃЁ ZnI2(s) . After this the remaining dilute acid was decomposed by placing copper leads of the anode and cathode of a 9V battery into the solution.

Results. Once the zinc metal, iodine crystals, and acetic acid solution were placed into the first test tube there was an obvious reaction. Obvious signs of a reaction included a darkening of color of the solution from clear to yellow and then to dark brown and a heating produced by the solution.

Reactant Amount Used In Initial Reaction (g) Moles of Substance with given mass

Zinc Metal 0.5113g .0078 mol

Iodine Crystals 0.497g .0019 mol

Table 1. Amount of reactant used in both, grams and moles.

Theoretical Yield- 0.6069g ZnI2(s)

Actual Yield- 0.5336g ZnI2(s)

Percent Yield- 87.92% (Actual Yield / Theoretical Yield x 100)

Group Number Percent Yield

1 53%

2 87.92%

3 92%

4 65.5%

5 100%

Table 2. Percent yields of all groups in the laboratory.

The Iodine was determined to be the limiting reagent in the reaction when provided with the given amounts. When using this information for the production of 1000 kg of ZnI2 the calculations showed that with the 87.92% yield, 904 kg ZnI2 would be needed. Compared to class data the percent yield obtained was fairly good. Other groups obtained lower percent yields or percent yields over 100% which seemed flawed.

Discussion. As seen above, the most cost efficient production of 1000 kg ZnI2 was determined. The Iodine was found to be the limiting reagent and