Correct Option
Methane (CH₄) is a highly flammable gas naturally present in coal seams and released during mining operations. When methane mixes with air (which contains oxygen) within an explosive range (typically 5% to 15% methane by volume), it forms a highly combustible mixture. The ignition of this mixture by a spark, open flame, or hot surface can lead to severe explosions, commonly known as 'firedamp' explosions. This phenomenon accounts for the majority of explosions in underground mines, particularly coal mines.
Incorrect Options
- Hydrogen and Oxygen: While a mixture of hydrogen and oxygen is highly explosive, these gases are not typically found in significant concentrations to cause widespread explosions in mines.
- Oxygen and acetylene: This mixture is used in industrial applications like welding and cutting (oxy-acetylene torches) under controlled conditions. It is not a common cause of mine explosions.
- Carbon dioxide and methane: Carbon dioxide (CO₂) is a non-flammable gas. Its presence in a mixture with methane would dilute the methane and reduce, rather than cause, its explosive potential. Therefore, this pair does not lead to explosions.