How Do Metals React With Dilute Acids?

How Do Metals React With Dilute Acids?

This experiment aims to study the displacement reaction between hydrochloric acid or sulphuric acid with metal. And also study the reactivity of metals in acid. The reaction between a metal and hydrochloric acid solution is an example of a single displacement reaction. Metals react with dilute hydrochloric acid to give metal chloride and hydrogen gas. The hydrogen gas is seen in the form of effervescence (bubbles) in the test tube when metal granules are added to dilute hydrochloric acid.                          

                                        M (s) + 2HCl (aq) ? M Cl₂ (aq)  + H₂ (g)   (M = Zn, Fe, Mg)

Metals also react with sulphuric acid to produce metal sulphate and hydrogen gas.

                                   M (s) + H₂SO₄(aq) ? MSO₄(aq)  + H₂ (g)   (M = Zn, Fe, Mg)

But all metals do not undergo a reaction with acids such as dil. HCl or dil. H₂SO₄. For example, copper does not react with these acids. Copper reacts with only dil. HNO₃ to give copper nitrate.

Let’s study this experiment in detail.  In this experiment, apparatus and materials are required: Test tubes and a test tube stand, a Petri dish, A piece of sandpaper, magnesium, aluminium, zinc, iron, copper, and dil. hydrochloric acid, dil. sulphuric acid, dil. nitric acid.

Experiment Procedure

To perform this experiment, steps to be followed in the following manner:

1. Take five test tubes and fill each with 10 mL of hydrochloric acid.
2. The metal pieces (the exposed surface of the metals should be approximately the same) must be cleaned using sandpaper.
3. Add a piece of magnesium, aluminium, zinc, iron and copper individually to each test tube.
4. Each test tube begins to bubble as hydrogen gas evolves, but the gas bubbles’ evolution rate differs in each case. Observe carefully.
5. Now take the second set of five test tubes.
6. Fill them with 10 mL of dilute sulphuric acid each.
7. Clean the fresh metal pieces using sandpaper.
8. Add a piece of magnesium, aluminium, zinc, iron and copper individually to each test tube.
9. Observe the rate of evolution of hydrogen gas if the gas is evolved.
10. Now take two test tubes.
11. Fill them with 10 mL of dilute nitric acid each.
12. Clean the fresh magnesium and copper pieces using sandpaper.
13. Add a piece of magnesium and copper individually to each test tube.
14. Observe carefully to see if the evolution of gas is seen or not.

In this experiment, we studied the reactions of different metals with different dilute acids and arranged the metals according to their reactivity. With dil. HCl and dil. H₂SO₄, magnesium reacts most vigorously, followed by aluminium, zinc and iron. These reactions produced hydrogen gas and the respective metal salts.

Copper does not react with both dil. HCl and dil H2SO4. With dil. HNO3, magnesium reacts like the other acids, producing hydrogen gas, while copper produces copper nitrate, water and nitric oxide gas instead of hydrogen. Thus, nitric acid is not a suitable acid to compare the reactivity of different metals.

FAQs on Metals Reacting With Dilute Acids