VI-1 Chem 2115 Experiment # 6 PERIODIC RELATIONSHIPS

Notebook observations:
IIIA. Halide Salts: Prepare a table of observations with three columns (solid, with water, and with hexane)
and with rows for KCl, KBr and KI. Your observations should include color (distinguishing the color
white from “colorless”), whether or not the solid dissolves, and the color of liquids.
IIIB. Halide Salt Reactions: Prepare a table of observations with three columns (for Cl2, Br2 and I2) and
with rows for KCl, KBr and KI (similar to the table shown above). In each of the 9 boxes, put your
observations of the colors of the (bottom) water layer and the (top) hexane layer. The hexane layer color
will be crucial in determining what halogen is present after any possible reaction has taken place. (Note:
Five of these systems should have I2 in the hexane layer after the halogen addition, three should have Br2
and one should have Cl2. If your results do not agree with this, check with your instructor.)
At this point you should be able to write the chemical reactions for samples that exhibited a reaction. For
example, when chlorine (Cl2) is mixed with the iodide ion (I - ) a reaction should be observed (after shaking,
the hexane layer is the characteristic color if iodine, I2). Since you began with the iodide ion (KI) and
ended up with the iodine molecule (I2), this is evidence of a reaction:
In many cases you will not observe any reaction (the color of the hexane layer exhibits the characteristic
color of the halogen you began with). In this case, no reaction took place between the halogen and the
halide.
IV. Determination of an unknown halide
Take one of the unknown solutions, which will contain KCl, KBr, or KI, and determine which it is by
applying a test used in Part IIIB. To do this, it will be necessary to plan a procedure to distinguish between
the solutions.
Notebook observations:
IV. Unknown halide salt determination. Write the unknown number of your salt solution. Include a
clear description of the procedure you have chosen in your lab notebook. Write down your observation of
the outcome of this procedure and your conclusion about the identity of your unknown.
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