We recently broke a mercury thermometer.

This was unfortunate, but then we realized we could salvage the mercury from it and maybe do something interesting.

There's only a tiny blob, but this should be enough.

We don't normally keep mercury compounds at Kymplier as they are so toxic and a dangerous cumulative poison.

Well, the best thing we know of for dissolving metals is nitric acid.

So here's a small amount of 68% concentrated nitric acid.

Let's add a few drops and see what happens.

The reaction is pretty vigorous and as per usual with a metal reacting with nitric acid.

It gives off brown fumes of nitrogen dioxide.

As the acid reacts and becomes more dilute the speed of the reaction slows right down as you can see.

So we add a bit more acid to keep the reaction going fast.

In the middle of the beaker you can see a white solid starting to crystallize out of solution.

Pretty soon this spread and a lot of material crystallized as you can see.

We're guessing that this is mercury nitrate crystallizing.

There's still a bit of mercury remaining so we continued acid addition to get this to react.

This dissolved the precipitate, which supports our theory of this being water soluble mercury to nitrate.

And over about 30 minutes the rest of the mercury reacted.

Okay we've got a nice clear solution.

But this contains excess nitric acid.

So now we need to somehow neutralize this.

We decided to use about a gram of sodium carbonate dissolved in 7 or 8 mils of water.

Once dissolved we added this dropwise to the mercury and nitric acid mixture.

In addition this gave off CO2 gas but also formed the temporary precipitate which looks like mercury to carbonate.

Which then re-dissolved in the solution.

After just a few drops were added the mixture turned white and crystallized again.

So we measured out 5 mils of water and added this to the mixture to see if we could dissolve the precipitate before continuing with neutralization.

We also measured the pH.

Still strongly acid so we've still got some neutralization to do.

What's interesting though is that the white precipitate this time didn't dissolve with the addition of more water.

So we continued neutralization with the sodium carbonate solution.

The mixture turned a slightly cream color and it looks as though we've got more of the white precipitate being produced.

Let's check the pH again.

It's neutral now.

We're not totally sure what the white precipitate is but we're guessing that it's either a basic insoluble mercury carbonate.

Or it's a mercury 1 salt produced as the nitric acid became more dilute and reacted with the mercury.

We've got a piece of aluminium foil here.

Let's see if there's enough mercury in the solution to react and amalgamate the mixture.

Because aluminium is a more reactive metal it will react with the mercury compounds in solution, reducing them and forming mercury metal.

The mercury metal will then amalgamate with the aluminium forming an aluminium-mercury alloy.

We've spread the mixture out a bit using the pipette.

Let's watch and see how this reacts over the next few minutes.

Thank you.

Thank you.

You can see a reaction occurring and gas is being produced.

Normally, aluminium isn't reactive as it's protected by a thin layer of aluminium oxide on the surface.

But now that this is removed, we can see that the underlying aluminium metal is actually pretty reactive stuff.

This is what remains when taken out of the water and left to dry.

The top layer of aluminium foil has pretty much reacted with the water.

Forming white aluminium hydroxide.

Aluminium metal made reactive in this way using mercury salts is an unorthodox, but powerful reducing agent and can be used in organic synthesis.

We'll try to use our mercury solution in a future video and see if we can perform an organic compound reduction.

Stay tuned.

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