What is volatality?

Answer 1

Mercury, like all other substances have what is called a "vapour pressure". A good way to understand what is meant by this is to think about a can of butane, or CNG or the liquid inside your cigarette lighter. Now, while trapped inside that canister, it remains liquid. Why? Because of the pressure the canister is under, or the pressure that the gas of that liquid in the canister is under. Now, if the canister is allowed to leak slightly, the pressure inside the canister is higher than outside (at sea level, say) and the gas escapes, lowering the pressure pushing down on that liquid and it boils (which is really just the liquid turning into a gas because the molecules of the liquid are too tightly packed and want to be free from "banging into each other". Now, at sea level, you can boils liquid Mercury and you will get mercury vapour that is poisonous and will condense pretty quickly onto solid object. But, a small portion of it will still be present in the air because of its vapour pressure-the amount is very small, but it exists! it is because of vapour pressure that Hg is easily absorbed into the lungs! Look up vapour pressure for a better explanation....