HNO₂ + HCN → H₂CN + NO₂

This is an oxidation-reduction (redox) reaction:

HCN is an oxidizing agent, HNO₂ is a reducing agent.

Reactants:

• HNO₂ – Nitrous acid , Hydroxidooxidonitrogen
  • Other names: HNO2 , [NO(OH)] , Nitrosyl hydroxide , Dioxonitric acid
  • Appearance: Pale blue solution
• HCN – F , Ormonitrile (substitutive)|Hydridonitridocarbon (additive)}}
  • Other names: Hydrogen cyanide , Ormic anammonide|Hydrocyanic acid|Prussic acid|Methanenitrile , Hydrogen cyanide, liquefied ... show moreHydrocyanic acid , Formonitrile , Prussic acid , [CHN] , HCN show less
  • Appearance: Colorless liquid or gas ; Colourless gas or liquid with characteristic odour ; Colorless or pale-blue liquid or gas (above 78°F) with a bitter, almond-like odor. [Note: Often used as a 96% solution in water.]

Products:

• H₂CN
• NO₂ – Nitrogen dioxide
  • Other names: Nitrogen(IV) oxide , Deutoxide of nitrogen , Nitrogen peroxide ... show moreNO2 , NO2(.) , Dinitrogen tetroxide (see notes) , Nitrogen tetroxide , Dinitrogen tetroxide show less
  • Appearance: Brown gas ; Reddish-brown gas or brown or yellow liquid with pungent odour ; Yellowish-brown liquid or reddish-brown gas (above 70°F) with a pungent, acrid odor. [Note: In solid form (below 15°F) it is found structurally as N2O4.]