[mercury01]

Hello,

I started to work on a laboratory that uses mercury in some teaching experiments and they put a water layer over the liquid metal to avoid it's vapour to escape from the recipient. They use arround 300mL in a beaker, exposed to air.

I don't think this is the correct procedure. Someone suggested to use liquid paraffin instead of water.

I can't find information on this in the web. Can I have some advice on this matter please?

[curiouscat]

What's the experiment?

[mercury01]

What's the experiment?

It's a plant physiology experiment, for the biology courses, where a branch is attached to a glass pipette containing water, which is immersed in liquid mercury. As the plant transpires a mercury column goes up through the pipette.

[Arkcon]

Sounds like a mercury manometer.  Is the mercury really exposed?  Can you draw us a diagram or find a diagram of this experiment online for us to see?

[mercury01]

I tried to draw. If the water layer protects the mercury then I think it's not exposed but I don't know if it this works.

[billnotgatez]

Do you put the water on top of the Mercury before placing the pipette assembly in the beaker?

[mercury01]

Yes, as the mercury is stored with this water layer already.