`K_(4)[Fe(CN)_(6)]` can be used to detect one or more out of `Fe^(2+), Fe^(3+). Zn^(2+), Ag^(+), Ca^(2+)`:

Options

A. only `Fe^(2+),Fe^(3+)`
B. only `Fe^(3+), Zn^(2+), Cu^(2+)`
C. all but not `Ca^(2+)`
D. All of these

Answer

D

Explanation

`Fe^(2+) +[Fe(CN)_(6)]^(4-) to` white precipitate , `Fe^(3+) +[Fe(CN)_(6)]^(4-) to` Prussian blue precipitate.
`Zn^(2+) +[Fe(CN)_(6)]^(4-) to`Bluish white/white precipitate , `Cu^(2+) +[Fe(CN)_(6)]^(4-) to` chocolate brown precipitate
`Ag^(+) +[Fe(CN)_(6)]^(4-) to` white precipitate , `Ca^(2+) +K_(4)[Fe(CN)_(6)] to` white precipitate.