Important
Not a redox reaction!
Equation
Metal Carbonate (s) → Metal oxide (s) + Carbon dioxide (g)
Effect of Reactivity of metals on the thermal stability of metal carbonates
Summary
Sodium and Potassium → higher up reactivity series. Their carbonates are very stable to heat. Carbonates of metals → below sodium in reactivity series → decompose to form oxide of metals and carbon dioxide Silver carbonate, silver oxide produced is thermally unstable. It further decomposes to form silver
| Metal | Action of heat on carbonates |
|---|---|
| Potassium Sodium | No decomposition. Carbonates of these highly reactive metals are stable to thermal decomposition (High thermal stability) |
| Calcium Magnesium Zinc Iron Lead Copper | Carbonates of these less reactive metals → are less stable to thermal decomposition. → these metal carbonates will decompose to form metal oxides andcarbon dioxide upon strong heating. As Reactivity of metals decreases → thermal stability of metal carbonates decreases → thus ease of thermal decomposition of metal carbonates increases |
| Silver | Silver carbonate → readily decomposed upon heating → to produce silver, oxygen and carbon dioxide |
Important
- no stable compound, aluminium carbonate, Gold Carbonate, Platinum carbonate exists, that is why it is not in the table
Important
The more reactive a metal is, the more difficult it is to decompose its carbonate by heat
- Means that more reactive metals → form carbonates → that are more stable to heat than others.
Thermal stability of metal carbonates → tested by heating them in dry test tube
compare reactivity of metal to carbon and hydrogen, lower can reduce higher cannot reduce