Question

Which of the following does not give an oxide on heating
1) MgCO3
2) Li2CO3
3) ZnCO3
4) K2CO3

Answer 1

Ans:K2CO3.
Thermal stability of of metal carbonates is related to the position of the metal in the reactivity series. The more reactive the metal is, the more difficult it is to decompose its compounds. Therefore, sodium and potassium carbonates are not affected by heat.