How do we differentiate between `Fe^(3+)` and `Cr^(3+)` in group lll?

Options

A. By taking excess of `NH_(4)OH`
B. By increasing `NH_(4)^(+)` ion concentration
C. By decreasing `OH^(-)` ion concentration
D. Both (B ) and (C )

Answer

D

Explanation

In a group III of analysis, addition of `NH_(4)Cl` increases `NH_(4)^(+)` ion concentration produced from `NH_(4)OH` due to common ion effect.