In the previous video we created an adduct of urea and hydrogen peroxide, which is a

useful oxidizing agent.

In this video we're going to create another hydrogen peroxide adduct, only this time with

sodium carbonate.

The adduct is called sodium percarbonate, but this name is misleading because no additional

oxygen has been added into the carbonate molecule.

Compare this with persulfates or peroxides and you'll see the difference.

We're going to use a 250 mL beaker equipped with a stir bar.

For the reaction, first of all we've measured out 100 mL of water.

As you'll see later on this reaction does also work with a degree of dilution, but for

the first attempt we're going to get everything concentrated.

This goes into our beaker.

Next we've weighed out 59 grams of anhydrous sodium carbonate.

For the hydrated crystal you'll need to adjust the weight accordingly.

We're using the 1.25 molar ratio compared to what we need for the reaction in order

to see if we can get as much of the hydrogen peroxide to form the adduct as possible.

Let's get the stirrin' dialed up.

And now we add the sodium carbonate.

It's going to take some stirring, but it should all dissolve.

Interestingly when anhydrous sodium carbonate dissolves it also warms up a little bit.

We'll leave this for a few minutes to get back down to room temperature again.

Okay now for our next reactant.

Here we have 75 mL of a 30% by weight solution of hydrogen peroxide in water.

We cooled this down in the fridge so it's at about 10 degrees C.

Okay here's our sodium carbonate stirring.

So let's add the hydrogen peroxide.

And within seconds the mixture turns solid with crystals.

It's really quite solid.

Breaking it up and stirring it, we can see it's quite gelatinous.

A little bit like an insoluble carbonate or hydroxide.

We covered up the beaker and chilled it in the fridge for an hour in order to maximize

the precipitate.

And now time to filter.

We're using a large funnel because there's quite a lot of it.

Now for the tricky part, getting it dry.

We repeatedly broke up the solids, then packed it down again in the filter.

And did this for two hours.

Here's what we've got.

The product is not completely dry, but perhaps best described as fluffy with clumps.

It weighs just over 80 grams, and since the maximum yield of product is about 70 grams,

we know that it's still got water in there and so a yield calculation is meaningless.

So we'll have to desiccate it if we want a dry product.

First we did a test to check the filtrate to see if this still contains an appreciable

amount of sodium peroxide.

We tried to get a very light amount of hydrogen peroxide.

On pouring it into a scratched and rather dirty beaker, it effervesces.

Definitely an indication of hydrogen peroxide.

Now for a few drops of manganese dioxide suspended in water.

Again, there seems to be quite a lot of hydrogen peroxide left in the filtrate, so the process

is certainly not 100% efficient.

Now we know what you're thinking.

Does this work with regular strength peroxide?

So we did a second experiment on a smaller scale.

This time we used 15 mils of water.

And 6 grams of sodium carbonate.

We added this to the water and dissolved to form a clear solution as before.

This took a few minutes.

Then we diluted down 10 mils of our 30% hydrogen peroxide to 40 mils volume using water.

This is now about an 8% solution.

Like you can get in the pharmacy.

The sodium carbonate is stirring.

So let's add the diluted peroxide as before.

Well, there's no crystallization but there is some turbidity in the mixture as you can see.

Unfortunately, stopping the stirring we can see though that this seems to be some effervescence in the mixture.

So we put the mixture in the fridge for an hour to get it nice and chilled.

And here's the result.

Gelatinous water.

The white precipitate has appeared as before.

But a much more dilute version.

So let's filter it off.

With the smaller amount of solid it was definitely a lot easier to dry.

This time we've got 1.7 grams of product.

This is below a 20% yield.

So you can prepare this product using pharmacy peroxide.

But with a low yield.

We also tried dissolving the carbonate in warmed peroxide directly.

But this didn't work and resulted in a lot of decomposition.

Okay, time for a quick test.

We've got some of our first batch of product in a small beaker.

And here's some manganese dioxide suspended in water.

It decomposes quite vigorously.

But if you recall our previous video on the urea peroxide adduct.

Not as vigorously as that did.

Looking at the figures of the percentage of peroxide by weight in each adduct.

This is surprising as they are quite close.

So this product seems to be a bit more stable.

Here's a small amount in a petri dish.

And some ethanol.

Let's see if it decomposes and supports combustion well.

Well the ethanol is burning and there's an orange color due to the sodium.

But nothing really spectacular.

It looks like the sodium carbonate absorbs the water that is created due to the decomposition of the peroxide forming a solid hydrate.

Whilst the oxygen is released quite slowly.

All you can really tell is that the flame is a little bit bigger than normal.

The urea compound is a lot more exciting.

But perhaps boring is a good thing when it comes to hydrogen peroxide adducts.

Apparently this can also be used as a concentrated form of hydrogen peroxide for reactions.

So we'll be experimenting with this.

And we'll report back if we find any interesting uses.

Otherwise we'll be mixing up some oxytocin or laundry detergent.

Thanks for watching and stay tuned.

Thanks for watching and stay tuned.