2K4[Fe(CN)6] + 6HNO3 → 2K2[Fe(NO)(CN)5] + 2HCN + O2 + 4KNO3 + 2H2O
Potassium hexacyanoferrate(II) react with nitric acid to produce pentacyanonitrosoferrate(II) potassium, hydrogen cyanide, oxygen, potassium nitrate and water. Nitric acid anhydrous. This reaction takes place at a temperature of 0-10°C.