Multiple choice

Which of the following is the most toxic gas?

  1. Carbon dioxide

  2. Carbon monoxide

  3. Nitrogen

  4. Hydrogen
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Carbon monoxide is extremely toxic because it binds to hemoglobin 240 times more strongly than oxygen, preventing oxygen transport and causing asphyxiation. CO2 and N2 are asphyxiants at high concentrations but less immediately toxic, while hydrogen is flammable but not typically described as 'toxic' in the same way as CO.

Keep practicing — related questions