Title: Reactivity of Halide Ions Purpose: To observe the reactions of halide ions. To determine the identity of the halide in unknown solutions. Materials: AgNO3 – silver nitrate NaCl – sodium chloride NaF – sodium fluoride KBr- potassium bromide KI – potassium iodide Na2S2O3 – sodium thiosulfate Ca(NO3)2 – calcium nitrate starch solution NaOCl – bleach test tubes and holder

Procedure: Part I 1. Place 2 mL of NaF, NaCl, KBr, KI solutions into separate test tubes. 2. Label the test tubes to identify their contents. Use white paper under test tube rack. 3. Add 1 mL Ca(NO3)2 to each test tube. 4. Record the color of any precipitates in your data table.

Procedure: Part II 1. In another set of clean, labeled test tubes, add 2 mL each of NaF, NaCl, KBr, KI solutions. 2. Add 1 mL of AgNO3 to each test tube. 3. Add 2 mL of Na2S2O3 to each test tube that contained a precipitate in step 2. 4. Record your observations in your data table.

Procedure: Part III 1. Place 2 mL of NaF, NaCl, KBr, KI solutions into a new set of test tubes. 2. Add 5 mL of starch solution to each tube. 3. Add 3 drops of NaOCl (bleach) to each test tube. 4. Record your observations in your data table.

Procedure: Part I V 1. Save the results from Parts II and III for comparison!!! 2. React the unknown sample as you did in parts II and III. 3. Compare the results to identify the unknown substance.

Data and Observations Part I Part II Part II Part III Halide Ca(NO3)2 AgNO3 AgNO3+ NaOCl + Na2S2O3 starch NaF NaCl KBr KI Unknown

Post lab assignment. Each group will submit the following: 1. One, clean, neat copy of your data table. 2. Conclusion: Did you accomplish your purpose? (Refer back to the purpose of the experiment. - If you did, tell why you were successful. - If you did not explain why there were problems. 3. Questions: a. What is a halide ion? b. What were the four halide ions in this experiment? c. Identify which part of the procedure (Part I, II or III) confirmed the presence of each ion. d. How do you know (c)? e. What was the identity of the unknown? How can you tell? f. For Parts I and II of the procedure, write the chemical equation (reactants only, leave products blank) for the reaction that took place. Please be sure that each member of the lab group keeps a copy of this information for future reference!!!

Data and Observations - Results Part I Part II Part II Part III Halide Ca(NO3)2 AgNO3 AgNO3+ NaOCl + Na2S2O3 starch NaF white ppt clear no change no change NaCl clear white ppt dissolve no change KBr clear pale-yellow dissolves no change ppt KI clear yellow-tan does not turns blue ppt dissolve Unknown