Explain the following: (a) Be(OH)_2 dissolves in sodium hydroxide but Mg(OH)_2 does not. (b) Beryllium halides are polymeric in nature.

Explain the following: (a) Be(OH)_2 dissolves in sodium hydroxide but

1.	Explain the following: (a) Be(OH)_2 dissolves in sodium hydroxide but Mg(OH)_2 does not. (b) Beryllium halides are polymeric in nature.
Answer» SOLUTION :(a) `Be(OH)_2` is amphoteric and therefore, it dissolves in NaOH forming sodium beryllate : `Be(OH)_2 + 2NaOH to Na_2BeO_2 + 2H_2O` On the other hand, `Mg(OH)_2` is basic and does not dissolve in NaOH. (B) The BERYLLIUM halides are electron deficient COVALENT compounds because they have only FOUR electrons in the valence shell. Therefore, to complete their octets, they undergo polymerisation.