Correct Answer - B
In the second group of basic radicals, `H_(2)S` gas is passed through the solution. In case, the original solution is prepared in dilute `HNO_(3)` then `H_(2)S` will be oxidised to sulphur which will appear as a yellow precipitate or yellow turbidity.
`2HNO_(3) rarr H_(2)O + 2NO_(2) + O`
`H_(2)S + O rarr H_(2)O + S`
This will interfere with the detection of `Cd^(2+)` and `As^(3+)` ions which also form yellow precipitates of CdS and `As_(2)S_(3)` respectively
