we recently got hold of some really nice quality sulfur but we couldn't think of

what we could do with it apart from making gunpowder but as chance would have it we also

had some old hydrogen the rock side solution of unknown strength lying around so we thought we'd

have a go that actually making sulfuric acid and in the process seeing if we could estimate that

the rock side strength so we rigged up this rather unusual apparatus let's take a quick guided tour

here's a glass funnel coated

with tin foil to protect it a bit from heat this is suspended above a few centimeters above a thick

sheet of tin foil we've connected the funnel to a short silicone hose which with the aid of some

pdfe plumbing tape leads to a glass tube going into a 500 milliliter flask the tube goes to

the bottom of the flask so it will go beneath the surface of any liquid and then we've got

an

airtight outlet tube leading to a vacuum pump when the pump is on air will get drawn all the

way through the apparatus let's place our 70 mils of unknown strength hydrogen peroxide into the

flask and with everything set up let's test the system

this is working pretty good

here's 10 grams of sulfur placed on the tin foil sheet under the funnel

we turned this into a boat and set fire to the sulfur

it's quite hard to light but once a portion of it melts it begins to burn sustainably

the pump is on and now the sulfur dioxide produced by the burning sulfur should get sucked up into the

apparatus. The inside of the flask appears cloudy, but there's no sulfur dioxide coming

out of the pump output, so we can tell that it's being absorbed by the hydrogen peroxide.

As the sulfur melts the fire spreads and more sulfur dioxide is produced.

Perhaps due to the hot gas, or perhaps because of the reaction taking place, the solution

in the flask begins to heat up quite considerably especially as the burning becomes more vigorous.

Most of the sulfur has now burned and we're starting to notice some sulfur dioxide coming

through the pump.

output, so some is now getting through without being absorbed.

You can see a lot of condensation.

The mixture is quite hot.

The sulfur has now pretty much all burned up.

Here's our cooled reaction mixture.

We're not sure if there's any peroxide remaining but we figure it's good enough.

We transfer this into a beaker.

First let's check the pH of the solution.

One or even less.

This is extremely acidic so we've definitely got sulfuric acid generated in here.

Normally you'd use a barium salt to precipitate that.

Without the sulfate due to barium sulfate being extremely insoluble.

But we don't have any soluble barium salts so we'll have to use calcium chloride instead.

We make up a strong solution of about 15 grams of calcium chloride in 50 ml of water.

Notice how it gives off quite a lot of heat as it dissolves.

Enough to fog the sides of the beaker.

So we let this cool right down.

And now we add it to our solution.

A thick gelatinous white precipitate of calcium sulfate is produced.

We stirred this really well to make sure everything had reacted.

And then set up for filtration.

We washed the beaker out with cold water, and then used this to wash the precipitate.

It takes quite a long time to remove the excess water, but eventually we get a solid cake

in the filter which we can remove.

We placed this into a Pyrex baking dish and placed in the oven at 120 degrees C for a few hours in order to dry off the water.

A slight yellow color was observed during this process, but this disappeared as the product dried out completely.

As it baked we broke up any lumps so that the fine powder could become completely dry.

Here's our product.

13.7 grams of calcium sulfate.

This is probably not completely anhydrous and likely to contain a lot of hemhydrate.

We'll assume for the purposes of our calculation that it is hemhydrate rather than completely anhydrous.

By doing some math we can conclude that our starting peroxide solution must contain at least 4.3% hydrogen peroxide by weight.

But there's quite a margin for error in the process so it could be a lot higher than this.

We'll see.

We'll see if we can find a use for the peroxide in an upcoming video.

Thanks for watching and stay tuned.