In which of the pairs of ions given, there is an ion that forms a co-ordination compound both aqueous sodium hydroxide and ammonia and another ion that forms a co-ordination compound only with aqueous sodium hydroxide ?

Options

A. `Pb^(2+),Cu^(2+)`
B. `Zn^(2+),Al^(3+)`
C. `Cu^(2+),Zn^(2+)`
D. `Al^(3+),Cu^(2+)`

Answer

B

Explanation

`Zn^(2+),Al^(3+)`
(I)`Zn(HO)_(2)+2NaOHrarr[Zn(OH)_(4)]^(2-)+2Na^(+)`
`underset("Anhydrous")(ZnCl_(2))+4NH_(3)rarrunderset("zinc chloride")underset("Tetraamine")(Zn(NH_(3))_(4))Cl_(2)`
(II) `Al(OH)_(3)+NaOHrarr[Al(OH)_(4)]^(-)+Na^(+)`
`Al^(3+)+3NH_(3)rarrAl(NH_(3))_(3)`