Question

How many of the following cation shows characteristic coloured ppt. with \(K_4[Fe(CN)_6]\)?

\(Cu^{2+},\ Ca^{2+},\ Ba^{2+},\ Fe^{3+},\ Zn^{2+},\ Mg^{2+},\ Mn^{2+}\)

Answer 1

Answer is : 3

\(Mn^{2+} + K_4[Fe(CN)_6] \rightarrow \underset{(\text{Pale pink coloured ppt.}) }{Mn^2[Fe(CN)_6]}\)

\(Ba^{2+} + K_4[Fe(CN)_6] \rightarrow \text{No visible colour change}\)