LPG Leakage: Understanding the Pungent Smell

Liquefied Petroleum Gas (LPG), commonly used as cooking fuel, is naturally odorless. However, for safety reasons, a substance is added to give it a distinct smell. This smell acts as a crucial warning signal if the gas leaks from the cylinder or pipes, helping to prevent potential accidents like fires or explosions.

Identifying the Warning Gas in LPG

The question asks to identify the specific gas that gives LPG cylinders their characteristic pungent smell, serving as a warning agent. Let's examine the options:

• Methane: While methane is a component of natural gas, it is odorless. It is not the primary odorant added to LPG.
• Odonil: Odonil is typically a freshener product and not an industrial additive for LPG.
• Ethyl Mercaptan: This chemical compound, also known as ethanethiol, is widely used as an odorant in LPG and natural gas. It has a strong, pungent, garlic-like or rotten smell, making it effective for detecting leaks even in small concentrations. Its chemical formula is $\text{C}_2\text{H}_5\text{SH}$.
• All of these: Since only Ethyl Mercaptan is the correct odorant among the specific chemical options, this choice is incorrect.

The Role of Ethyl Mercaptan in LPG Safety

Ethyl Mercaptan is added to LPG in very small quantities. Its potent smell is designed to be easily detectable by the human nose well below the lower explosive limit (LEL) of the gas. This allows people to quickly identify a leak and take necessary safety measures, such as turning off the supply, ventilating the area, and avoiding any open flames or sparks.

Therefore, the gas responsible for the pungent smell in LPG cylinders as a warning of leakage is Ethyl Mercaptan.