Question

What are the hazards associated with the use of the elemental halogens in the laboratory?

Answer 1

You have not given us much context with regard to the experiment, but we can make a few suggestions.

Explanation:

`F_2` and `Cl_2` are room temperature gases; they are also poisonous, and thus unsuitable for use in a laboratory. It is true that bromine, `Br_2`, is a room temperature liquid (`"boiling point"` `59` `""^@C`), but bromine is one of the most corrosive liquids that I know, and could cause horrendous burns, so this material is quite unsuitable for even an undergraduate lab. Chlorine and bromine water are known, and their risk is mitigated by their lower concentrations in water. Finally, iodine is available as a solid; an ethanolic solution is much more convenient to use.

Does this address the gist of your question?