It’s easy to make hydrogen gas at home or in a lab using common chemicals and everyday materials. Once you have the gas, you can use it for a variety of interesting science projects. Of course, you’re not “making” hydrogen, since it’s an element. It is produced by chemical reactions that release it. Here’s how to make hydrogen safely.
Make Hydrogen Gas – Method 1
The electrolysis of water (H2O) is one of the easiest way to make hydrogen gas. Electrolysis breaks the water into hydrogen gas and oxygen gas. So, you can collect impure oxygen using this method, too.
Materials
Only basic materials are needed for this method:
- Water
- 9-volt Battery
- 2 Paperclips (or wire)
- Container filled with water
Procedure
- Unbend the paperclips and connect one to each terminal of the battery.
- Place the other ends, not touching, into a container of water. Congratulations! You have electrolysis.
- You’ll see bubbles coming off both wires. The one with more bubbles is giving off pure hydrogen. The other bubbles are impure oxygen. You can test which gas is hydrogen by holding a lit match or lighter over the container. The hydrogen bubbles will burn; the oxygen bubbles will not burn.
- Once you’ve identified the hydrogen source, you can collect it. Collect the hydrogen gas by inverting a water-filled tube or jar over the wire producing the hydrogen gas. The reason you want water in the container is so you can collect hydrogen without obtaining air. Air contains 20% oxygen, which you want to keep out of the container in order to keep it from becoming dangerously flammable. Don’t collect the gas coming off both wires into the same container, since this is a mix of hydrogen and oxygen and is flammable. If you wish, you can used a second container with water to collect the impure oxygen.
- Disconnect the battery. Stopper or cap the container of water and gas before turning it rightside-up. Label your container.
Make Hydrogen Gas – Method 2
While electrolysis is a good method to get hydrogen, there are two improvements that greatly improve yield. The first is to use pencil “lead” (pure graphite) as electrodes. The second tip is to add a pinch of salt to the water to serve as an electrolyte.
Graphite makes good electrodes because it is electrically neutral and won’t dissolve during electrolysis. Salt dissociates into its ions in water and increases the current flow, boosting the electrolysis reaction.
Materials
Aside from the addition of pencils and salt, the significant change is that you have more options for the battery.
- 2 Pencils
- Salt (sodium chloride or Epsom salt)
- Cardboard
- Water
- Battery (could go as low as 1.5V, since there is an electrolyte)
- 2 Paperclips or pieces of electrical wire
- Container filled with water
Procedure
- Remove the erasers and metal caps from the pencils and sharpen both ends to expose the pencil lead.
- Add a pinch of salt to the container of water.
- Use the cardboard to support the pencils in the salt water. Place the cardboard over your container of water. Insert the pencils through the cardboard so that the lead is submerged in the liquid, but not touching the bottom or side of the container.
- Attach a wire to each pencil. Connect each wire to a battery terminal.
- Collect the gas as before, in a container that has been filled with water.
Make Hydrogen Gas – Method 3
Chemical reactions often release hydrogen gas. One reaction is between zinc and hydrochloric acid to produce zinc chloride and hydrogen gas:
Zn (s) + 2HCl (l) → ZnCl2 (l)+ H2 (g)
Most metals react with acid to release hydrogen, so feel free to substitute iron or aluminum if it’s more readily available. Collecting the gas is a bit trickier because of the acid. It’s a good idea to perform this reaction within a fume hood and to wear goggles and gloves. One method is to invert a glass container of acid over the metal so the gas displaces the liquid. It’s much safer to invert an empty collection bottle over the reaction and let hydrogen displace air. Hydrogen is lighter than air and will rise. The collection bottle will contain some air (and oxygen) at the end of the process.
Materials and Procedure
- Hydrochloric acid or muriatic acid
- Zinc granules (or strips of aluminum or iron filings)
Mixing the acid and metal immediately releases bubbles of hydrogen gas. Be careful to avoid touching the acid. Also, expect heat production by this exothermic reaction.
Make Hydrogen Gas – Method 4
Strong bases also react vigorously with many metals. Sodium hydroxide (NaOH) and potassium hydroxide (KOH) both contain the element hydrogen and release hydrogen gas. For example, aluminum and sodium hydroxide react to produce hydrogen and sodium aluminate:
2Al (s) + 6NaOH (aq) → 3H2 (g) + 2Na3AlO3 (aq)
Materials
- Sodium hydroxide (commonly sold as a drain cleaner)
- Aluminum (often included in drain cleaners or you can use aluminum foil)
- Water
Procedure
- Place drain cleaner and aluminum in a glass dish. Don’t use metal or plastic because the drain cleaner could react with the metal. Heat produced by the reaction could damage plastic.
- Fill a glass container with water to collect the hydrogen gas.
- Invert the container of water over the pile of chemicals and collect the hydrogen gas.
Safety Information
- Familiarize yourself with the safety information for any chemicals you may use. In particular, hydrochloric acid (a strong acid) and sodium hydroxide (a strong base) are caustic and can cause chemical burns. If you use these chemicals, be sure to wear gloves, safety glasses, and other protective gear.
- Store hydrogen gas away from open flames, heat, and ignition sources.
- Be aware that mixing hydrogen gas with oxygen or air (which contains oxygen) increases its flammability because oxygen is an oxidizer.
If you enjoyed making hydrogen gas and would like to try a similar project, try making chlorine gas.
References
- Fabbri, Emiliana; Schmidt, Thomas J. (October 5, 2018). “Oxygen Evolution Reaction—The Enigma in Water Electrolysis.” ACS Catalysis. 8 (10): 9765–9774. doi:10.1021/acscatal.8b02712
- Giddey, S.; Kulkarni, A.; Badwal, S.P.S. (2015). “Low emission hydrogen generation through carbon assisted electrolysis.” International Journal of Hydrogen Energy. 40: 70–74. doi:10.1016/j.ijhydene.2014.11.033
- Practical Physics (2008). “Electrolysis of Water and the Concept of Charge.” (archived)
Hello,
First at all, thank you for the teaching about how to collect the Hydrogen. Second, I had a doubt while I was readng yor post. In the methods 3 and 4, where are used metals and quimichal products in reaction, the equation does not have Oxygen as result. Why they still have the oxygen when I collect the gas?
In case of the answer be the oxygen already in the recipient, with a vaccum bag or something like it, I would be capable to have just Hydrogen in the bag?
Right Mateus,
Some of these reactions release hydrogen gas, so if you are careful, you can collect it without nitrogen or oxygen from air. The easiest way to do this is to place a collection container over the reaction. If the reaction is in water, submerge the container in the water (no air space), invert it over the reaction, and collect the hydrogen gas bubbles. For dry ingredients, you also collect hydrogen by placing a container over the reaction. In this case, the hydrogen is lighter than air, so it rises to the top of the container and eventually displaces most of the air. But, there is still some nitrogen and oxygen collected this way, so you either need to produce enough hydrogen to eliminate most of the air or else accept the contamination (depending on your needs).
According to the instructions, methods 1 and 2 will also produce impure oxygen. Why is it impure? Are you assuming there is something other than just Hydrogen and Oxygen in the water? Or is some hydrogen also released from the lead producing oxygen?
Hi Chris,
The oxygen is impure because you’re collecting it by displacing air. Purity increases as displace more nitrogen (and other gases in air). Also, you can expect some water vapor in the collected gas.