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+)` ion reacts with aqueous NaOH and `NH_3` and forms a co-ordination compound.
`Zn^(2+)` + 4NaOH `` [`Zn(OH)_4]^(2-)` + 4`Na^(+)`
`Zn^(2+)` + 4`NH_3` `` [ Zn(`NH_3)_4]^(2+)`
`AL^(3+)` ion reacts only with NaOH and not with `NH_3`
`Al^(3+)` + 4NaOH `` `[Al(OH)_4]^(-)` + `4Na^(+)`