The correct sequence of thermal stability
Question:

The correct sequence of thermal stability of the following carbonates is

1. $\mathrm{BaCO}_{3}<\mathrm{CaCO}_{3}<\mathrm{SrCO}_{3}<\mathrm{MgCO}_{3}$

2. $\mathrm{MgCO}_{3}<\mathrm{CaCO}_{3}<\mathrm{SrCO}_{3}<\mathrm{BaCO}_{3}$

3. $\mathrm{BaCO}_{3}<\mathrm{SrCO}_{3}<\mathrm{CaCO}_{3}<\mathrm{MgCO}_{3}$

4. $\mathrm{MgCO}_{3}<\mathrm{SrCO}_{3}<\mathrm{CaCO}_{3}<\mathrm{BaCO}_{3}$

Correct Option: , 2

Solution:

Thermal stability of Alkaline earth metals carbonates increases down the group.

because down the group polarizing power of cation decreases. So thermal stability increases.

Hence, Thermal stability order :

$\mathrm{MgCO}_{3}<\mathrm{CaCO}_{3}<\mathrm{SrCO}_{3}<\mathrm{BaCO}_{3}$