Question

Is water boiling at ${100^ \circ }C$ a physical or chemical property?

Answer 1

The chemical properties can be distinguished from physical properties depending upon the type of changes associated with the. Determine the changes that take place during boiling to find out it is a physical or a chemical property.

Complete answer:
A chemical change or reaction involves the breaking and forming of new bonds. The existing chemical species undergoes a major change in its properties to form a completely new chemical species that has different physical and chemical properties. Chemical changes are usually accompanied by colour change, evolution or absorption of heat that changes the temperature of the container, evolution of gases or change of state (like precipitation of any compound).
Physical changes are changes associated with the physical attributes of a substance like its shape, size or its state. No new chemical compound is formed in a physical change and the bonds present in the existing molecule remain intact.
Boiling of water is a phase transformation in which the liquid state of water gets rapidly converted into its vapour form by the absorption of heat supplied to it. At ${100^ \circ }C$ the water molecules present in liquid state acquire sufficient thermal energy (throughout the bulk) to get rid of the forces of attraction exerted by surrounding molecules and move far apart which transforms them into the vapour phase.
The hydrogen-oxygen bonds present in water remain intact through the boiling process and no new substance is formed. Only the interspatial arrangement of water molecules changes which brings about a change of state.
Hence. Water boiling at ${100^ \circ }C$ is a physical property.

Note:
A phase change or a state change means the same thing when liquid gets transformed into a gas. But a phase separation can be between two liquids which are considered the same state. Hence, phase and state do not mean the same thing.