The isomer(s) of [Co(NH₃)₄Cl₂] that has/have a Cl–Co–Cl angle of 90°, is/are :

The reaction of H₃N₃B₃Cl₃ (A) with LiBH₄ in tetrahydrofuran gives inorganic benzene (B). Further, the reaction of (A) with (C) leads to H₃N₃B₃(Me)₃. Compounds (B) and (C) respectively, are :

Consider the following reactions,


The compound [P] is :

5 g of zinc is treated separately with an excess of

(a) dilute hydrochloric acid and
(b) aqueous sodium hydroxide.

The ratio of the volumes of H₂ evolved in these two reactions is :