Which gas is used as a fuel in Cigarette Lighters?  

Butane is a liquid at lower pressure and when the pressure is released it turns to a gas which can be easily ignited. So, butane is used as a fuel in lighters and camping stoves.

Butane is a versatile hydrocarbon that exists as a liquid under low pressure due to its physical properties. When the pressure is reduced, it quickly converts into a gas. This transformation occurs because butane has a relatively low boiling point, which allows it to vaporize easily at standard atmospheric pressure and temperatures.

This ability to transition from a liquid to a gaseous state makes butane an ideal choice as a fuel. In lighters and camping stoves, the liquid butane is stored under pressure in small containers. When the valve of the lighter or stove is opened, the pressure inside the container is released, causing the liquid butane to evaporate and turn into a gas. This gas mixes with oxygen from the air and can be easily ignited, producing a steady and controlled flame.

Additionally, butane's high energy density ensures efficient burning, providing a strong and consistent heat source. Its portability, ease of storage, and clean combustion make it a popular fuel option for portable applications like lighters and camping equipment.