Qualitative Analysis of Halide Ions Lab #______ Background: In this experiment, you will be given four solutions, each containing one of the following halide ions (F‐, Cl‐, Br‐, or I‐). You will first determine the properties of these four halide ions by combining them with various solutions. You will then create your own experiment to determine the identity of unknown halide solutions. Purpose: Materials: Procedures: Part A: 1) Obtain 5 test tubes and a test tube rack. Make sure the test tubes are clean before beginning the lab. 2) Number the test tubes 1‐5 with the wax pencil. 3) For each halide a. In test tube #1, combine 5ml of the halide with 1 dropperful of calcium nitrate solution. Record detailed observations in data table 1. b. In test tube #2, combine 2ml of the halide with 5 ml of the starch solution and 2 drops of commercial bleach. Record detailed observations in data table 1. c. In test tube #3, combine 3 ml of the halide with 10 drops of silver nitrate solution. Record detailed observations in data table 1. d. In test tube #4, combine 3 ml of the halide with 10 drops of silver nitrate and then add 5 ml of ammonia solution. Record observations in data table 1. e. In test tube #5, combine 3 ml of the halide with 10 drops of silver nitrate and then add 5ml of sodium thiosulfate solution. Record observations in data table 1. 4) Once you have finished all five tests for the first halide, CLEAN the test tubes really well with water and then REPEAT step #4 for the other three halides, cleaning the test tubes in between each halide. Part B: Now Develop your OWN experiment below to test 2 unknown halides! Data Table 1 Halide Calcium Nitrate Silver Nitrate Silver Nitrate + Ammonia Silver Nitrate + Sodium Thiosulfate Fluoride Chloride Bromide Iodide 2 Unknowns Data Unknown #1‐ (#__) Unknown #2‐ (#__) Starch and Bleach Flow Chart‐ fill in the following flow chart based on your data findings Fluoride, Chloride, Bromide, Iodide
Add calcium nitrate Add Silver Nitrate Add starch and bleach Based on the Above Flow chart: Unknown #1 (#_____) is _________________________________ Unknown #2 (#_____) is _________________________________ Post Lab Questions: 1) Flow charts are a valuable tool in indentifying substances. If you were the president of a company that performed water testing, what economical advantages would there be to using flow charts? 2) Identify the halogens being described below: (Write your answer on the line provided‐ you may need to research these!) a. Large amounts of this halogen are used in water purification _____________________________ b. The most reactive halogen _________________________ c. A solid under standard conditions that produces a purple vapor _________________________________ d. In solution with alcohol, this halogen is used as an antiseptic _____________________________________ e. A pale greenish‐yellow gas ______________________________ f. The only liquid nonmetallic element under standard conditions _____________________________________ g. Added to common table salt to aid in the prevention of a goiter _________________________________________ 3) Write true or false next to the following statements about halogens. a. The halogens are nonmetals ________________________ b. The halogens form diatomic molecules in their elemental state_______________ c. The term halogen means salt former ___________________ d. The halogens are the most reactive nonmetals _________________ e. The halogens have a high attraction for electrons _______________