Question

when you go into your labatory to carry out the halogen displacement reactions, you already know from lecture that the order of reactivity, and electronegativity, is Cl2 > Br2 > I2, so you are able to predict which results to expect from the various combinations of halogen and halide salt.

let us suppose, though, that you are a student with a color perception disorder, so that you see the color of the halogens differently from other students. and suppose the halogen samples arent identified for you, but are given as unknowns, labeled X2, Y2, and Z2 for the halogens, and X- , Y-, and Z- for the corresponding halides. you are to identify the relative reactivity of the unknowns, and hence their identity, by mixing different combinations of halogen and halide, and identifying the halogen product from the color of the hexane layer after extraction.

as a start, you first add the free halogens to your test tube, extract into hexane, and get the results in the figure below (test tube picture)

next you mix the following combinations of reagents and record the resulting color of the hexane in your test tubes, giving the resilts in the table below.

now rank the unknows from kost electronegative (1) to least electronegative (3)

predict the color that would result from the following reagnant mixtures

now that you have identified the relative reactivites ( and electronegativities) of the unknowns, match them to their correct halogen identities.

Y2 22