Question

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

Answer 1

Hint: This question is based on the concept of different states in which water exists at different surrounding temperatures. Water generally exists in three states – solid ice, liquid water and gaseous steam. Water changes states on the basis of the temperature conditions of the surroundings.

Complete answer:
Water has a freezing point of 0 degrees Celsius under normal temperature and pressure conditions (STP). When liquid water is cooled to this temperature, it freezes and transforms into a solid. When this happens, water molecules occupy certain positions in a lattice.
When heated to temperatures above 0 degrees Celsius, solid water melts and returns to its liquid state. This temperature equates to 32 degrees Fahrenheit on the Fahrenheit scale and 273.15 degrees Kelvin on the Kelvin scale.
When taken out of its container and placed in an open environment, this state of water has a very low viscosity and, as a result, rapidly deforms (this state of water has the potential to ‘flow' without much opposition from viscous stress). Water exists in the liquid state in the temperature range of 0 to 100 degrees Celsius under normal temperature and pressure conditions (STP).
Water vapour (also known as steam) is the gaseous state of water that exists at temperatures above 100 degrees Celsius. Evaporation and boiling are two different ways for liquid water to become gaseous.
Thus, at ${25^o}C$, water is in a liquid state.
At ${0^o}C$, water is in solid state i.e., ice.
At ${100^o}C$, water exists as vapour i.e., steam.

Note:
Over $70\%$ of the Earth's surface is covered by liquid water. Water, in its liquid condition, is required for all living species' metabolic processes. This is due to the fact that liquid water is a universal solvent and offers the environment for a wide range of biological reactions.