Question

Which of the following has the lowest ignition temperature?
A. Cow dung
B. Wood
C. Paper
D. Kerosene

Answer 1

Hint: Ignition temperature is the minimum temperature at which a combustible substance such as air or gas or other substance, must be heated up prior to burning in the absence of any source of the heat. We can say that the lowest temperature at which a substance catches fire and undergoes combustion liberating heat and light is called ignition temperature.

Step by step answer: The substance which has lower Ignition temperature catches fire easily. Here we have four options: cow dung, wood, paper & kerosene.
Kerosene is a petroleum product, so the ignition temperature of kerosene is low as compared to other given substances. The ignition temperature of kerosene is between 37 and 65 degree centigrade..

Hence, the correct choice is option (D).

Additional Information: There is a term called auto ignition temperature. The auto ignition temperature or kindling point of a substance is the lowest temperature in which it spontaneously ignites in a normal atmosphere without an external source of ignition, such as a flame or spark. This temperature is required to supply the activation energy needed for combustion
Auto ignition occurs when a mixture of gases or vapors ignites spontaneously with no external ignition source and after reaching a certain temperature, the auto ignition temperature.

Note: Students may confuse between Ignition temperature and auto ignition temperature. These both are different terms. The values for Ignition temperature and auto ignition temperature are different.