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Q.
The solubilities of carbonates decrease
down the magnesium group due to a decrease in :
Solution:
The solubility of the alkaline earth metal carbonates decreases down the group from $Mg$ to $Ba$. This is because of the fact that down the group with increasing size of cation the lattice energy as well as hydration energy also decrease but the change in hydration energy is more as compare to that of lattice energy.