Question

K4[Fe(CN)6] can be used to detect one or more out of Fe2+,Fe3+,Zn2+,Cu2+,Cd2+

Answer 1

All but Fe2+Fe2+

2ZnCl2+K4[Fe(CN)6]−→−−−−−CH3COOHZn2[Fe(CN)6]3↓(Bluish white)+4KCl2ZnCl2+K4[Fe(CN)6]→CH3COOHZn2[Fe(CN)6]3↓(Bluish white)+4KCl

2FeCl3+2K4[Fe(CN)6]−→−−−−−CH3COOHFe2[Fe(CN)6]3↓(Prussian blue)+12KCl2FeCl3+2K4[Fe(CN)6]→CH3COOHFe2[Fe(CN)6]3↓(Prussian blue)+12KCl

2Cu(NO3)2+K4[Fe(CN)6]−→−−−−−CH3COOHCu2[Fe(CN)6]↓(Reddish brown)+4KNO32Cu(NO3)2+K4[Fe(CN)6]→CH3COOHCu2[Fe(CN)6]↓(Reddish brown)+4KNO3

2Cd(NO3)2+K4[Fe(CN)6]−→−−−−−CH3COOHCd2[Fe(CN)6]↓(Bluish white)+4KNO32Cd(NO3)2+K4[Fe(CN)6]→CH3COOHCd2[Fe(CN)6]↓(Bluish white)+4KNO3

Thus except Fe2+Fe2+, all other ions gives Fe3+,Zn2+,Cu2+Fe3+,Zn2+,Cu2+ and Cd2+Cd2+ can be detected using K4[Fe(CN)6]K4[Fe(CN)6]
Hope it will help you.
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