why does there come out a foam like silver bubbles wen you mix dilute sulpheric acid and magnesium metal oxide

Dilute sulfuric acid means water is there also.

I suspect you have a mixture of magnesium oxide, magnesium, water, and sulphuric acid.

What happens depends on how much of each.

Magnesium and acid yields hydrogen bubbles
Magnesium and water yields hydrogen bubbles and magnesium hydroxide.

magnesium hydroxide and acid yields water and magnesium sulfate.

I suspect you have a mixture of all this.

When dilute sulfuric acid (H₂SO₄) and magnesium metal oxide (MgO) are mixed together, an interesting reaction takes place. The observation of foam-like silver bubbles is due to the formation of magnesium sulfate (MgSO₄), water (H₂O), and the release of carbon dioxide (CO₂) gas.

To understand why this reaction occurs, let's break it down step by step:

1. Magnesium oxide (MgO) is an ionic compound containing magnesium (Mg²⁺) and oxide (O²⁻) ions.

2. Sulfuric acid (H₂SO₄) is a strong acid consisting of hydrogen ions (H⁺) and sulfate ions (SO₄²⁻).

When magnesium oxide is mixed with sulfuric acid:

3. The acid dissociates, releasing hydrogen ions (H⁺) into the solution.

H₂SO₄ -> 2H⁺ + SO₄²⁻

4. The hydrogen ions (H⁺) react with the oxide (O²⁻) ions from magnesium oxide, resulting in the formation of water molecules (H₂O).

H⁺ + O²⁻ -> H₂O

5. The remaining sulfate ions (SO₄²⁻) combine with magnesium ions (Mg²⁺) from magnesium oxide to form magnesium sulfate (MgSO₄).

Mg²⁺ + SO₄²⁻ -> MgSO₄

During this reaction, carbon dioxide gas is also released:

6. Carbon dioxide (CO₂) is produced when the carbonate impurities present in the magnesium oxide react with the acid.

CO₃²⁻ + 2H⁺ -> CO₂ + H₂O

The formation of carbon dioxide gas bubbles, along with the water and the formation of magnesium sulfate, give the appearance of foam-like silver bubbles.

In summary, when dilute sulfuric acid reacts with magnesium oxide, the acid dissociates into hydrogen ions (H⁺), which react with oxide ions (O²⁻) to form water (H₂O). The remaining sulfate ions (SO₄²⁻) react with the magnesium ions (Mg²⁺) to create magnesium sulfate (MgSO₄). Additionally, the reaction of carbonate impurities with acid leads to the release of carbon dioxide gas (CO₂).