The correct order of thermal stability of the following metal carbonates is ans. BaCO3 < BeCO3 < MgCO3 < CaCO3 MgCO3 < CaCO3 < BaCO3 < BeCO3 BaCO3 < CaCO3 < MgCO3 < BeCO3 BeCO3 < MgCO3 < CaCO3 < BaCO3

The correct order of thermal stability of the given metal carbonates is BeCO3 < MgCO3 < CaCO3 < BaCO3.

This order is based on the stability of the metal carbonates with heat. Beryllium carbonate (BeCO3) is the least stable and decomposes easily when heated. On the other hand, Barium carbonate (BaCO3) is the most stable among the given options and requires a higher temperature to decompose.

The thermal stability of metal carbonates increases down the group in the periodic table. This is due to the increase in the size of the cations (metal ions) down the group which polarizes the anions (carbonate ions) to a lesser extent, thus making the carbonate more stable to heat.