Question

Which one of the following is the correct statement?
(a) B₂H₆ ∙ 2NH₃ is known as ‘inorganic benzene’.
(b) Boric acid is a protonic acid.
(c) Beryllium exhibits coordination number of six.
(d) Chlorides of both beryllium and aluminium have bridged chloride structures in solid phase.

Answer 1

(d) : Boric acid is a weak monobasic acid (K_a = 1.0 × 10^–9). It is a notable part that boric acid does not act as a protonic acid (i.e., proton donor) but behaves as a Lewis acid by accepting a pair of electrons from OH^– ions.
B(OH)₃ + 2H₂O →  [B(OH)₄]^– + H₃O⁺
BeCl₂ like Al₂Cl₆ has a bridged polymeric structure in solid phase generally as shown below.

Beryllium exhibits coordination number of four as it has only four available orbitals in its valency shell.
Also,