Q. Carbon dioxide is a constituent of which of the following gases?

1. Syngas
2. Water gas
3. Producer gas
4. Coal gas

Choose the correct answer using the codes given below:
Answer: 1, 2, 3 & 4
Notes: Syngas, or synthetic gas, is a fuel gas mixture primarily of hydrogen and carbon monoxide, with traces of carbon dioxide, produced from natural gas and coal. Water gas, derived from syngas, also consists mainly of hydrogen and carbon monoxide, with minimal carbon dioxide. Producer gas contains carbon monoxide, hydrogen, carbon dioxide, and nitrogen. Coal gas, produced from coal, includes hydrogen, carbon monoxide, methane, ethylene, carbon dioxide, and nitrogen.