JEE Main 2025 Chemistry question
Choose the correct tests with respective observations. (A) CuSO₄ (acidified with acetic acid) + K₄[Fe(CN)₆] → Chocolate brown precipitate. (B) FeCl₃ + K₄[Fe(CN)₆] → Prussian blue precipitate. (C) ZnCl₂ + K₄[Fe(CN)₆], neutralised with NH₄OH → White or bluish white precipitate. (D) MgCl₂ + K₄[Fe(CN)₆] → Blue precipitate. (E) BaCl₂ + K₄[Fe(CN)₆], neutralised with NaOH → White precipitate. Choose the correct answer from the options given below :
Answer: (4)
Solution
Cu²⁺ gives chocolate brown Cu2[Fe(CN)6]; Fe³⁺ gives Prussian blue Fe4[Fe(CN)6]3; Zn²⁺ gives white ppt K2Zn3[Fe(CN)6]2. A, B, C are correct.