StreakPeaked· Practice

ExamsJEE AdvancedChemistry

When K3[Fe(CN)6] reacts with freshly prepared FeSO4, a dark blue solid known as Turnbull's blue is formed. On the other hand, when K4[Fe(CN)6] reacts with FeSO4 in the complete absence of air, a white solid X is produced, which later turns blue when exposed to air. Additionally, if FeSO4 is mixed with NaNO3 and concentrated H2SO4 is carefully added along the side of a test tube, a brown ring forms. What is the chemical identity of precipitate X?

  1. Fe4[Fe(CN)6]3
  2. Fe[Fe(CN)6]
  3. K2Fe[Fe(CN)6]
  4. KFe[Fe(CN)6]

Correct answer: K2Fe[Fe(CN)6]

Solution

K2Fe[Fe(CN)6] is the white precipitate formed in the absence of air, which later turns blue upon oxidation when exposed to air.

Related JEE Advanced Chemistry questions

⚔️ Practice JEE Advanced Chemistry free + battle 1v1 →