3K3[Fe(CN)6] + 5KOH + Cr(OH)3 → 3K4[Fe(CN)6] + K2CrO4 + 4H2O
Potassium hexacyanoferrate(III) react with potassium hydroxide and chromium(III) hydroxide to produce potassium hexacyanoferrate(II), potassium chromate and water. Potassium hydroxide - diluted solution.