Production of Hydrogen - Online Tutor, Practice Problems & Exam Prep

• Hydrogen gas (H2) can be produced from reactions involving ionic hydrides and acids through a double displacement reaction, resulting in H2 and a salt.
• In the reaction of ionic hydrides with acids, the hydride ion (H-) reacts with the hydrogen ion (H+) from the acid to form H2 gas, while the metal from the hydride forms a salt with the acid's anion.
• The reaction needs to be balanced to ensure the number of atoms on both sides of the equation is equal, often requiring adjustment of coefficients in the chemical equation.
• Another method to produce H2 gas involves the reaction of reactive metals with strong acids like sulfuric acid or hydrochloric acid, where the metal is oxidized.
• In the oxidation reaction of metals with acids, the metal loses electrons and is ionized, while hydrogen ions (H+) from the acid are reduced to form H2 gas.
• The stoichiometry of the reaction between metals and acids must be adjusted to balance the hydrogen atoms on both sides of the equation.

From Ionic Hydrides

Now there are several reactions that produce hydrogen gas. We will take a look at 2 reactions. The first one comes from ionic hydrides. Now ionic hydrides can be used as a source for our H₂ gas molecules. Here we're going to say due to the basic nature of our hydride ion, it reacts with water or an acid to form H₂ gas.

Here we have H₂ from an ionic hydride, an example. Here we have it reacting with a metal hydride and some type of acid. Here, in order to determine what our products will be, we just have to break up our reactants into their respective ions. Here this would be M²⁺, that's where this two came from. And then here hydrogen is with a metal, so it's the hydride form. So -1 our acid here would be H⁺ and A^-.

Here we're going to do a double displacement reaction. So our -1 H and our +1 H will combine together to give us our H₂ gas molecule. And then we're going to say here that the two from our metal is going to come here and our one from our A^- is going to come here. That's going to give us MA₂. We need to balance this out here. We're going to say we have 3 hydrogens on the reactant side and only two on the product side.

I'm going to put a 2 here to give us 2H₂ gas molecules, giving us a total of 4 hydrogens on the product side. In addition to this, we have two A atoms. So to balance things out, I put a 2 here. So this would be an example of us using a metal or ionic hydride with an acid in order to produce H₂ gas.

Production of Hydrogen Example

Here it says complete and balance the following reaction. In this reaction we have a solid lithium hydride reacting with hydrofluoric acid. Remember to determine the products we break up our reactants into the respective ions. Lithium is a group 1A so it's plus one. Hydride is -1. This is an acid so it breaks up into our hydrogen ion plus fluoride ion.

This is going to be a double displacement reaction. So the hydrogens will combine together to give us H2 and the lithium and fluoride will combine together to give us lithium fluoride, aqueous. We need to balance this out, so let's see, we have one lithium on each side, we have two hydrogens on each side, and we have one fluoride on each side.

So in fact we're already done. This is our balanced reaction.

From Metal and Acid

Now we can also get the production of H₂ gas from a metal and an acid. Here we're going to say when reactive metals react with sulfuric acid or hydrochloric acid, the metal is oxidized and H₂ is formed.

In this example. Here we have our metal solid reacting with H⁺, which is coming from either sulfuric acid or hydrochloric acid. They will produce H₂ gas as a product and the metal itself is going to be ionized.

Here fits in Group 1A to become plus one in charge and to balance this out, we have two hydrogens on the product side but only one on the reactant side. So we have to place a coefficient of two here. This would represent our oxidation of a group 1A metal by an acid in order to generate hydrogen gas as a product.

Production of Hydrogen Example

Here it says in this example complete and balance the following reaction. Here we have aluminum solid reacting with hydrochloric acid. We know that this is going to generate H₂ as a product. So we can already put H₂ here as a product.

Now to determine the ionic component that's going to be formed, we're going to say that aluminum is in Group 3A, so it's going to be 3 plus in charge. Chlorine is a group 7/8, so it's -1. Remember, when the numbers in the charges are different, they don't cancel out. They crisscross. O₃ comes here and one comes here. That will give us aluminum chloride as a product.

Now here we need to balance this out. In order to do that, I'm going to put, let's see, we have 3 chlorines here, but only one here. But if I put a three here, the hydrogens would still not be balanced. We'd have three hydrogens here and then two over here. So we think about what's the lowest common multiple answer 6. So I'm going to put a six here, which gives us 6 chlorines and six hydrogens.

To balance out the number of hydrogens, I put a three here so my hydrogens are balanced. To balance out my chlorine, I need to put a 2 here. 2 * 3 gives me 6 chlorines, but now we have 2 aluminums on the product side so I'd have to put a 2 here. This represents my balance chemical reaction between aluminum solid and hydrochloric acid.

Complete and balance given reaction.

BaH₂(s) + H₂O(l) →

• A. BaH₂(s) + 2 H₂O(l) → 2 O₂(g) + BaH₄(aq)
• B. BaH₂(s) + 2 H₂O(l) → 2 H₂O₂(l) + Ba(s)
• C. 2 BaH₂(s) + 2 H₂O(l) → 2 Ba(OH)₂(aq)
• D. BaH₂(s) + 2 H₂O(l) → 2 H₂(g) + Ba(OH)₂(aq)

Complete and balance given reaction.

Zn(s) + H₂SO₄(aq) → 

• A. 2 Zn(s) + H₂SO₄(aq) → H₂(g) + Zn₂SO₄(aq)
• B. Zn(s) + H₂SO₄(aq) → H₂(g) + ZnSO₄(aq)
• C. Zn(s) + 2 H₂SO₄(aq) → 2 H₂(g) + Zn(SO₄)₂(aq)
• D. Zn(s) + 3 H₂SO₄(aq) → 3 H₂(g) + Zn(SO₄)₃(aq)