Science Buddies: "Ask an Expert"

Hi, I have a few questions.

1) What is the best way to make hydrogen gas?

2) What is the best way to fill a balloon with hydrogen gas?

3) What is a cheap way to make hydrogen gas?

4) Is it possible to make hydrogen liquid or even solid?

Hi coinjunky2!

At first blush, if you're in a hurry, I would suggest supplying each of your questions to answers.com.

Re: liquid/solid hydrogen, I suspect that specialized and expensive equipment is required.

Any other thoughts of others?

First, this involves working with acid, so make sure you wear eye protection, are in a well-ventalated room, have nothing anywhere near the table, have an adult supervise, and so on. You could really get hurt!

This describes how I used to make hydrogen when I was in 7th grade:
http://www.3rd1000.com/labs/hydrogen.htm

My science teacher (the most excellent Salvatore Trento) had all of the material on hand (so yours might as well), so it was fairly simple to do. I would fill a balloon with hydrogen and sometimes some oxygen (using a different procedure which I forget), and then would use a yard stick with a match on the end to cause a small explosion. Very cool, but dangerous!

And as far as liquifying it goes, I think that's beyond your (and my) skills since it would require very low temperatures and high pressure. But, it would be interesting to your project to describe what temperature (and/or pressure) it would require. Just as a guess, I'd say around -250 degrees Farenheight at normal pressure.

A simpler, safer way to make Hydrogen gas is through electrolysis of water. This requires no special chemicals or supplies.

In a nutshell, electrolysis is a method of seperating bonded compounds into their component elements by breaking their bonds with an electrical current.
Since water is easy to find and doesn't require much energy to break down, and contains Hydrogen as one of its components, it is an excellent subject for this reaction.
In our case, we would want to break water down, so:

2H20 -> 2H2 + O2
With H2O being water, and H2 being your Hydrogen gas.

This can be done by creating a very simple apparatus.
-> First, you will need some sort of container which will hold the water.
-> You will then need a smaller container to collect the gas in. Since you mention filling a baloon, a piece of about 1" diameter PVC pipe or something would work well.
-> You will need a power source with which to seperate the H2O into its component atoms, which include Hydrogen. I recommend using a regular new 9 volt battery. Anything higher would be unnecessary and dangerous.
-> You will need two small pieces of wire, and two metal paperclips.

1. Connect one wire to each terminal on your 9V battery.
2. Wrap the other end of each wire around a paperclip. Use plain metal paperclips, not painted or coated/plastic ones.
-> You should now have a battery with a paperclip attatched to each terminal by a wire.
3. Fill the container with tap water. Don't use filtered water. Filtered water contains fewer ions which are required for the current to flow through the water.
-> Each paperclip is an electrode. The paperclip connected to the positive terminal of your battery is the positive electrode, and the one connected to the negative terminal is the negative electrode. We are interested in the negative electrode because this is where the Hydrogen gas will form.
4. Place both electrodes into the container filled with water. Bubbles will immediately start to form around each paperclip. Place the PVC pipe over the negative electrode to capture the hydrogen gas. Place the balloon over the other end of the pipe so that the gas goes into the balloon.
-> Make sure not to get the battery wet.

That's it! You now have Hydrogen gas. If nothing happened, read on for some suggestions.

----->WARNING: Hydrogen gas is highly flammable. Keep your collected samples away from any open flame.<-----

<TIPS>
1. If bubbles do not form, make sure that you are using a new 9V battery and that the wires are securely fastened to both the METAL paperclips and the terminals on the battery.
If there are still no bubbles, you have extremely clean water without ions in it. Without ions, water can't conduct electricity. To add some ions to your water, dissolve some plain table salt into it. The salt, NaCl will dissolve into Na+ and Cl- ions which will help electricity flow through your water.
2. The pressure of the Hydrogen gas may not be enough to fill up your baloon. You may want to blow the balloon up a few times yourself so that it becomes a bit stretched and easier to fill up.
If you still can't get enough pressure to fill your baloon, you may just have to use a flask or test tube. Do this by filling the test tube with water, and then placing it upside down in your container of water, and then placing the electrode in thte tube. The hydrogen formed will displace the water in the tube.


In this reaction we are specifically interested in the Hydrogen (H2) gas. Since Hydrogen ions are positively (+1) charged, Hydrogen gas will form at the negatively charged electode in the experiment. This gas can be gathered by placing the negative electrode in an inverted test tube (or other container)

If you need to see some diagrams of the setup or need some additional information, try searching for "electrolysis of water lab" on Google.com or your favorite search engines.

Hope this helps.

Ian Whitfield says: "---->WARNING: Hydrogen gas is highly flammable. Keep your collected samples away from any open flame.<----- "

I'd like to amplify this statement a bit. Hydrogen gas can be quite dangerous in moderately large quantities.

One thing to be careful of in addition to open flames is sparks, especially since you'd be making the hydrogen with electricity.

Make sure to do this in a *well* ventilated room, or preferably outdoors.

I've been quite aware of the dangers of electrolysis ever since I was working at SRI and an experienced scientist (who should have known better) was careless with a cold-fusion electrolysis experiment and ended up almost being decapitated by an explosion.

I'm not saying you shouldn't do it, because it can be and is done very safely all the time by lots of people. Just don't be careless. With a balloon full of H2, about the worst that would be likely to happen is singeing off your eyebrows if it exploded, but still...

Just curious: what do you need hydrogen gas for?

Four words: aluminum foil and drano.