How many of the following reagents will not be useful in separating a mixture of `Zn^(2+)` and `Cu^(2+)` ?
`(i) H_(2)S` in acid medium
`(ii) H_(2)S` in an alkaline medium
`(iii)` Excess of NaOH solution
`(iv) NH_(3)` solution

Answer

2

Explanation

In excess amount of NaOH can separate the `Zn^(+2)` and `Co^(+2)`