The pair, in which ions are isoelectronic with AI³⁺ is :

Leaching of gold with dilute aqueous solution of NaCN in presence of oxygen gives complex [A], which on reaction with zinc forms the elemental gold and another complex [B]. [A] and [B], respectively are :

Number of electron deficient molecules among the following

PH₃, B₂H₆, CCl₄, NH₃, LiH and BCl₃ is

Which one of the following alkaline earth metal ions has the highest ionic mobility in its aqueous solution?