The correct order of increasing thermal stability of `K_(2)CO_(3),MgCO_(3),CaCO_(3),` and `BeCO_(3)` is

Options

A. `BeCO_(3)ltMgCO_(3)ltK_(2)CO_(3)ltCaCO_(3)`
B. `BeCO_(3)ltMgCO_(3)ltCaCO_(3)ltK_(2)CO_(3)`
C. `MgCO_(3)ltBeCO_(3)ltCaCO_(3)ltK_(2)CO_(3)`
D. `K_(2)CO_(3)ltMgCO_(3)ltCaCO_(3)ltBeCO_(3)`

Answer

B

Explanation

Thermal stability increases with increasing ionic character of carbonates.
As per Fajan’s rule, ionic character of cations increases in the order `Be^(2+)ltMg^(2+)ltCa^(2+)ltK^(+)`.