Question

.You are provided with three Watch Glasses , Containing Milk , Petrol
Mustard Oil. Suppose you bring a burning Candle near these materials
one by one , Which material will catch fire easily and Why?

Answer 1

Petrol can catch fire easily because its ignition temperature(lowest temperature to ignite spontaneously) is very low. Petrol is highly flammable as it contains lighter hydrocarbons that can catch fire easily. It does not even need a spark to catch fire, it is autoignited.
Oil is the next thing to catch fire as it also contains hydrocarbons but heavier than petrol. It needs to reach a very high temperature to catch fire.
Milk does not catch fire as it is a mixture of fats and water that are not at all flammable or combustible.