Discuss the diagonal relationship of Be and AI with regard to (i) action of alkali and (ii) the strucutre of their chloride.

Explanation

(i) Be and AI both react with NaOH to form sodium beryllate and sodium me aluminate respetively. Be dissolves in excess of NaOH to form `[Be(OH)_(4)]^(2)` where as forms `[AI(OH)_(6)]^(3-)` in exces of NaOH
`2H_(2) O + BE + 2NaOH to Na_(2) [Be (OH)_(4)]` (Salium beryllali) + `H_(2)`
`2AI + 6NaOH + 6H_(2) O to 2Na_(3) [AI (OH)_(6)]` (Sodium meta ilunivali + `3H_(2)`
(ii) Be `CI_(2)` is electron deficient, therefore, has polymeric chain structure In solid state.

` AICI_(3)` is also electron deficient. It exists as dimmer, i.e., `AI_(2) CI_(6)`