Reactions of Metal Carbonates with Acids
Metal carbonates react with acids to produce carbon dioxide, water, and a salt. The general reaction can be represented as:
- **Equation**: Metal Carbonate + Acid → Salt + CO₂ + H₂O
- **Example**:
- Calcium Carbonate + Hydrochloric Acid → Calcium Chloride + Carbon Dioxide + Water
- CaCO₃ + 2HCl → CaCl₂ + CO₂ + H₂O
- **Observation**: The evolution of gas (CO₂) can be observed as effervescence.

Reactions of Metal Hydrogen Carbonates with Acids
Metal hydrogen carbonates (or bicarbonates) also react with acids, producing a similar outcome:
- **Equation**: Metal Hydrogen Carbonate + Acid → Salt + CO₂ + H₂O
- **Example**:
- Sodium Bicarbonate + Acetic Acid → Sodium Acetate + Carbon Dioxide + Water
- NaHCO₃ + CH₃COOH → CH₃COONa + CO₂ + H₂O
- **Observation**: The reaction releases CO₂, leading to fizzing.

Reactions of Metallic Oxides with Acids
Metallic oxides, being basic in nature, react with acids to form salts and water:
- **Equation**: Metallic Oxide + Acid → Salt + H₂O
- **Example**:
- Magnesium Oxide + Sulfuric Acid → Magnesium Sulfate + Water
- MgO + H₂SO₄ → MgSO₄ + H₂O
- **Observation**: No gas is evolved, and the reaction typically results in a clear solution of the salt formed.

Conclusion
In summary, metal carbonates and hydrogen carbonates react with acids to produce salts, carbon dioxide, and water, characterized by effervescence. In contrast, metallic oxides neutralize acids to yield salts and water without gas release.