Which gas has a bitter almond odor and is produced by incomplete combustion of nitrogen-containing materials?

Which gas has a bitter almond odor and is produced by incomplete combustion of nitrogen-containing materials?

• A. CO2
• B. HCl
• C. SO2
• D. HCN

Answer: (D)

Bitter almond odor points to hydrogen cyanide, a gas produced when nitrogen-containing materials burn incompletely. In fires involving polymers and textiles that contain nitrogen—such as nylon, wool, or polyurethane foams—incomplete combustion can release HCN along with other products. HCN is highly toxic because it disrupts cellular respiration, which is why it’s emphasized in safety and SCBA training for smoke inhalation hazards. Other common combustion gases don’t have that almond-like smell: carbon dioxide is odorless, hydrogen chloride has a pungent irritant odor, and sulfur dioxide has a sharp, choking odor. So the gas that fits both the odor cue and the nitrogen-containing material combustion scenario is hydrogen cyanide.

Bitter almond odor points to hydrogen cyanide, a gas produced when nitrogen-containing materials burn incompletely. In fires involving polymers and textiles that contain nitrogen—such as nylon, wool, or polyurethane foams—incomplete combustion can release HCN along with other products. HCN is highly toxic because it disrupts cellular respiration, which is why it’s emphasized in safety and SCBA training for smoke inhalation hazards. Other common combustion gases don’t have that almond-like smell: carbon dioxide is odorless, hydrogen chloride has a pungent irritant odor, and sulfur dioxide has a sharp, choking odor. So the gas that fits both the odor cue and the nitrogen-containing material combustion scenario is hydrogen cyanide.