Reactions with Chlorine: Take 2 test tubes and add 1cm³ TTE (trichlorotrifluoroethane) and 1 cm³ chlorine water (a solution of chlorine in water) to each. Now add 1cm³ potassium bromide solution (KBr) to one tube and 1 cm³ potassium iodide solution (KI) to the other. Do you observe any color changes? Stopper the tubes with corks and shake them. What happens? Record your results.

Reactions with Bromine: Take 2 test tubes and add 1 cm³ TTE and 1 cm³ bromine water to each. Now add 1cm³ potassium chloride solution (KCl) to one tube and 1 cm³ potassium iodide solution (KI) to the other. Do you observe any color changes? Stopper the tubes with corks and shake them. What happens? Record your results.

Reactions with Iodine: Take 2 test tubes and add 1cm3 TTE and 1cm³ Iodine solution to each. Now add 1 cm³ potassium chloride solution (KCl) to one tube and 1 cm³ potassium bromide solution (KBr) to the other. Do you observe any color changes? Stopper the tubes with corks and shake them. What happens? Record your results.

Controls: Take three test tubes and add 1cm³ TTE to each. To the first, add 1cm³ chlorine water, to the second 1cm³ bromine water, and to the third 1 cm³ iodine solution. The TTE will tend to extract the chlorine, bromine, and iodine into it (the lower layer), and thus you will see the colors of theses three elements and be able to tell when they are present or absent in your experiments.

On the basis of your observations, complete and balance the following equations. If you observed no reactions, write N.R.

Questions: Which of these three halogens (Cl₂, Br₂, I₂) is the most reactive? Which is the least reactive? Why do you suppose fluorine was not included in the experiment? Where would it have ranked? Why?