Question

Explain the observation made when each of the gases in mixed with

(a) bromine in a dark place

Answer 1

At room temperature, the vapor pressure of bromine is about 200 mmHg (roughly 0.25 atm).

So if the jar is sealed, some of the bromine will evaporate to a partial pressure of 0.25 atm (assuming there was enough liquid in the first place). Since bromine gas is the same brownish-red color as bromine liquid, the jar will appear to be filled with a brownish-red gas.

If the jar is not sealed, the bromine vapor will eventually escape and fill the room (until there is no liquid remaining). Not healthy.