[LHM]

Each of these solutions is added to a mixture of aqueous sodium bromide and chloroform, CHCl₃. Which one will give a positive test for aqueous bromine when the solutions are vigorously mixed?

A) NaCl solution
B) NaI solution
C) NaI₃ solution
D) chlorine water

I feel like it has to do with their reactivities, but I'm not really sure. How do you tell?

[opti384]

I think you are right that it has to be with the reactivity of halogens.

[LHM]

So I'm not sure if this is right but does it have to do with the Br- ion replacing the H atom in a substitution reaction to form CBrCl₃, and then since Cl is smaller and more electronegative, it'll replace the Br in CBrCl₃? What difference will chlorine water and Cl^- ions make in this question?

[opti384]

From CBrCl3, couldn't it be iodine replacing bromine?

[LHM]

Can iodine replace bromine? I thought that the reactivity for halogens, from most reactive to least reactive was: F>Cl>Br>I? Unless that doesn't apply here or something...?