Multiple choice K4[Fe(CN)6] is used in the identification of A. Fe+2 B. Cu+2 C. Cd+2 Only (A) Only (B) Only (C) (A) and (B) All of these Reveal answer Fill a bubble to check yourself D Correct answer Explanation This option is correct because K4[Fe(CN)6] gives blue color with Fe+2 ion, due to Fe2[Fe(CN)6] and also gives chocolate precipitation with Cu+2 due to the formation copper ferrocyanide.