Reactions of Acids with Metals

When a metal reacts with an acid, the reaction produces a salt and hydrogen, In the equation:

Acid + MetalSalt + Hydrogen

An example of a reaction between an acid and a metal is when hydrochloric acid reacts with magnesium.

Hydrochloric acid + magnesiummagnesium chloride + hydrogen

Or more specifically

2HCl + MgMgCl2 + H2

Magnesium chloride is the salt that is produced and hydrogen gas is also produced.

In every acid + metal reaction, hydrogen gas is produced. Which means, the only difference is the salt. Let’s look at two more examples:

Nitric acid + Sodium ⮕ Sodium nitrate + hydrogen

Sulphuric acid + Calcium ⮕ Calcium sulphate + hydrogen

  • Highlighted in red is the salt produced

The salt name depends on which acid and metal is used. The first part of the name comes from the metal used. For example with our earlier example:

Hydrochloric acid + magnesiummagnesium chloride + hydrogen

  • As we used magnesium, the name of the salt starts with ‘magnesium’
  • Because we used hydrochloric acid, the name of the salt ends with ‘chloride’

Remember these salt endings!

AcidSalt Ending
Hydrochloric acidChloride
Sulphuric acidSulphate
Nitric acidNitrate

You can tell the reaction has taken place, as you can observe fizzing (bubbles rising within the acid), which is the hydrogen gas being released.

The more reactive the metal is, the more vigorous the reaction will be This means the reaction will take place quicker and more bubbles will be released For example, magnesium will have a more vigorous reaction with acids than iron.

  • Some unreactive do not react with dilute acids. For example, with metals such as copper or gold, wont react with dilute acids.

Hydrogen gas is always produced in metal and acid reactions. You can test to make sure it’s hydrogen gas

Testing for Hydrogen gas

When the reaction with the metal and acid reacts…

1. Place a boiling tube over the reacting acid and metal – this is to collect the hydrogen gas

2. Put a lighted splint in to the boiling tube

3. If hydrogen is present, then you will hear a squeaky pop