Which of the following best describes the characteristics of methane?

• A. Odorless, tasteless, colorless, explosive
• B. Smelly and hazardous
• C. Bright red and reactive
• D. Nonflammable

Answer: (A)

Methane is a colorless, odorless, tasteless gas that is highly flammable and can form explosive mixtures with air. It’s the simplest hydrocarbon and makes up the bulk of natural gas, so in mines it can accumulate quietly if ventilation isn’t keeping up. Because it has no smell on its own, leaks can go undetected without proper monitoring—odorants are often added to gas to help with detection. Its flammable range in air is roughly 5% to 15%, meaning a leak within that band can ignite if there’s an ignition source. So describing methane as odorless, tasteless, colorless, and explosive best captures its key characteristics. The other choices misstate its properties—methane isn’t inherently smelly, isn’t bright red, and it is flammable, not nonflammable.