<prompt> Smell of bitter almonds is seen in poisoning withPhosphorusHydrocyanic acidNitric acidOxalic acid  <response>: Cyanide can be a colorless gas, such as hydrogen cyanide HCN or cyanogen chloride CNCl, or a crystal form such as sodium cyanide NaCN or potassiumcyanide KCN. Cyanide sometimes is described as having a bitter almond smell, but it does not always give off an odor, and not everyone can detect this odor. Ref ganongs review of medical physiology 25e p143 