Metal carbonates decompose on heating to give metal oxide and carbon dioxide. Which of the metal carbonates is most stable thermally?

1. MgCO3

2. CaCO3

3. SrCO3

4. BaCO3



Hint:  Down the group thermal stability increases
BaCO3 thermally most stable because thermal stability increases with increasing cationic size. Ba2+ cation has the maximum size among all given cations, that is, Mg2+, Ca2+ and  Sr2+