Question

Why is $L{i}_{2}C{O}_3$ decomposed at a lower temperature whereas $N{a}_{2}C{O}_3$ at higher temperature?

Answer 1

Lithium carbonate is less stable than sodium carbonate as Li is less electropositive than sodium. As lithium carbonate is not stable to heat, it decomposes at lower temperature. Small sized Li polarizes large carbonate ion which leads to formation of $L{i}_{2}O$ and $C{O}_2$. Since, sodium carbonate is very stable, it decomposes at high temperature.