Question

Arrange the following in order of increasing thermal stability:
$BeS{O}_4,MgS{O}_4,CaS{O}_4$

• A. $BeS{O}_4<MgS{O}_4<CaS{O}_4$
• B. $BeS{O}_4>MgS{O}_4>CaS{O}_4$
• C. $BeS{O}_4<CaS{O}_4<MgS{O}_4$
• D. $CaS{O}_4<MgS{O}_4<BeS{O}_4$

Answer 1

The correct option is A $BeS{O}_4<MgS{O}_4<CaS{O}_4$

As the size of the metal ion increases, the thermal stability of the sulphates of alkaline earth metal also increases. This is beacuse the polarizing power of metal cation decreases down the group.
Hence, thermal stability follows the order:
$BeS{O}_4<MgS{O}_4<CaS{O}_4$
So option (a) is correct.