To separate and identify the ionis in a mixutre that may contain `Pb^(2+), Cu^(2+)` and `Mg^(2+)` use the reagents `H_(2)S, HCI` and NaOH. They should be added in the order:

Options

A. `HCI, H_(2)S, NaOH`
B. `H_(2)S, HCI, NaOH`
C. `HCI, NaOH, H_(2)S`
D. `NaOH, H_(2)S, HCI`

Answer

A

Explanation

HCI precipitates `Pb^(2+)` only, `H_(2)S` precipitates `Pb^(2+)` and `Cu^(2+)` and `NaOH precipitates all.