Question

The properties of most of the ionic solids deviate from their ideal ionic character because the lattice undergoes some distortion. Cations are usually smaller than anions and have a higher effective nuclear charge. The outer electron cloud in a cation is more firmly held than in an anion. The loose electron cloud of an anion, when attracted by the electron cloud of a cation, gets distorted. This phenomenon is known as polarization. Due to this phenomenon, the electron cloud of an anion shifts towards the cation which decreases both the magnitude of positive charge on the cation and the negative charge on the anion. In other words, covalent character develops in the ionic bond

Which of the following alkali metal carbonates decompose on heating?

• A. $L{i}_{2}C{O}_3$
• B. $N{a}_{2}C{O}_3$
• C. $K_{2}C{O}_3$
• D. $R{b}_{2}C{O}_3$

Answer 1

The correct option is A $L{i}_{2}C{O}_3$

Lithium carbonate and magnesium carbonate are thermally unstable. They decompose on heating:
$L{i}_{2}C{O}_3\stackrel{\Delta }{⟶}L{i}_{2}O+C{O}_2$
Carbonates become more thermally stable down the group.