Why does solubility of sulphates decrease down the group?

For sulphates: Solubility decreases as you go down the group. The lattice dissociation enthalpy and hydration enthalpy both decrease as you go down the group. The hydration enthalpy decreases more than the lattice dissociation enthalpy. Therefore the enthalpy of solution becomes more endothermic (or less exothermic).

Why alkali metal sulphates are more soluble than alkaline earth metal sulphates?

(i) Solubility ,(a) Alkali metals . Nitrates , carbonates and sulphates of alkali metal are soluble in water . Their , solubility , however, increases as we move down the group since the lattice enthalpies decrease more rapidly than the hydrogen enthalpies . (b) Alkaline earth metals.

Why alkali metal carbonates are more soluble than alkaline earth metal carbonates?

Because of smaller size and higher ionic charge, the lattice enthalpies of alkaline earth metals are much higher than those of alkali metals and hence the solubility of alkali metal hydroxides is much higher than that of alkaline earth metal hydroxides.

Why does the solubility of alkaline earth metal carbonates and sulphates decrease?

Why does the solubility of alkaline earth metal carbonates and sulphates in water decrease down the group? The ability of alkaline earth metal cations to hydrate themselves decreases down the group due to decrease in charge density.

What determines the trend in solubility down the group?

However, although the lattice enthalpy decreases going down the group, the solvation enthalpy also decreases because larger cations have lower charge density. The trend in the overall enthalpy, which is the difference between the lattice enthalpy and solvation enthalpy, should be what determines the trend in solubility.

Why does solubility depend on lattice energy?

When we move down along the group hydration energy decreases so the solubility also decreases as they are directly related. When the anionic size is small, then as we move along the group the change in cationic size will affect the values of lattice energy .Hence the Solubility depends on lattice energy .

What determines the solubility of a compound in water?

Solubility of any compound is decided by its hydration enthalapy and lattice energy. For any compound if H. E > L. E then the compound is soluble in water. As we go down the group the size of cation increases due to which both H. E and L. E decreases but due to large size of anion (Carbonate and Sulfate) the H. E decreases more rapidly than L. E.