Which of the following statements are not true?

1. Sulphates and hydroxides of alkali metals are more soluble than those of alkali metals.
2. Solubility of alkaline earth metal sulphates increases down the group.
3. Solubility of alkaline earth metal hydroxides decreases down the group.
4. Alkaline earth metal ions have greater hydration enthalpies than alkali metal ions.

For the sulphates of alkaline earth metals, the cations are much smaller than the anions. On moving down the group, the change in size of the cations does not cause a significant change in ∆H_lattice, but ∆H_hydration becomes less negative. As a result, ∆H_solution becomes less negative and the solubility of alkaline earth metal sulphates decreases down the group. For the hydroxides of alkaline earth metals, the size of the anions and cations are of the same order of magnitude. On moving down the group, less energy is required to break the lattice as the size of cations increases, but the change in ∆H_hydration is comparatively small. Consequently, the ∆H_solution becomes more negative and the solubility of alkaline earth metal hydroxides increases down the group.