Question

Which of the following is not a physical property?
A.Density
B.Temperature
C.Boiling point
D.Colour
E.Flammability

Answer 1

Flammability is the ease with which any combustible substance can be ignited by causing fire or combustion or even an explosion. Flammability can only be observed or measured during a chemical change known as combustion. Combustion is a chemical reaction that occurs when a fuel reacts with oxygen to produce light and heat.

Complete step by step answer:
A physical property is a feature of a matter that is not related with a change in its chemical composition. Familiar examples of physical properties include colour, hardness, density, melting and boiling points, and also electrical conductivity of any substance.
Flammability is the capability of a matter to burn or ignite. When a matter burns, it combines with oxygen and changes to a different substance. This is a property of a chemical change. Chemical properties are the characteristics of a matter that can be measured or observed only when a matter undergoes a change to become an entirely different kind of matter. Thus, Flammability is not a physical property. It is a chemical change or the one that can be observed when a substance changes into something else.

Therefore, the correct answer is option (E).

Note: Gases are not so difficult substances to define in terms of flammability. For a gas or air mixture, if it is flammable at all, then there exists a lower limit of fuel concentration below which self-sustained burning does not occur. It is usually the vapour given off from liquids which burns rather than the liquids themselves. Solids burn by the heat from the flames causing volatile gases to be given off from the surface of the material.