Question

What is the physical state of water at:
(a) ${25^o}C$
(b) ${0^o}C$
(c) ${100^o}C$

Answer 1

The physical state of any particular compound depends on the molecular pattern in which the compound exists under the specific physical conditions. The molecules and the intermolecular nature with the spaces between the molecules differ from one state of matter to another.

Complete step by step solution:
The physical state of water of the state of matter in which the water exists depends on the temperature in which the water exists. This is because the change in temperature causes the volume to change which causes the molecular pattern to change. The reduction in temperature is responsible for reducing the volume and that causes the close packing of the molecules together with very low intermolecular space. The increase in temperature can also cause an increase in volume. The change of state of water depends on the freezing point and the boiling point. The temperature falling below freezing point changes the state of water from liquid to solid. The temperature moving above boiling point causes the change of state from liquid to a gaseous state. The freezing point of water is ${0^o}C$ and the boiling point of water is ${100^o}C$ .
(a) The first temperature in which water is present is ${25^o}C$ which is above the freezing point but lower than the boiling point. This means that at this temperature water exists in a liquid state. (b) The next temperature is ${0^o}C$ in which water exists in solid state or in the form of ice. This is the temperature at which the water starts to change from the state of water to ice. (c) The next temperature is ${100^o}C$ and at this temperature water changes to a gaseous state. This is because ${100^o}C$ is the boiling point of water and at this temperature, the liquid form of water starts changing to a gaseous state, which is steam.

Note:
Changing state of matter depends on the different physical properties of matter which includes temperature, pressure, volume and many more. All these have a specific effect on the state of matter depending on the relative packing of the molecules and interaction between the molecules.