A phase diagram is a graphical representation of the equilibrium conditions between different states of matter, such as solid, liquid, and gas, as a function of temperature and pressure. The phase diagram of water shows the regions where water exists as a solid ice , liquid, and gas water vapor under various combinations of temperature and pressure.The phase diagram of water consists of three main regions, each representing a state of matter:1. Solid region Ice : This region is found at low temperatures and high pressures. In this region, water molecules are arranged in a crystalline lattice structure, and the water is in its solid state, known as ice.2. Liquid region: This region is found at moderate temperatures and pressures. In this region, water molecules are closely packed but have enough energy to move around, allowing the water to flow. This is the liquid state of water that we are most familiar with.3. Gas region Water vapor : This region is found at high temperatures and low pressures. In this region, water molecules have enough energy to break free from their neighbors and move independently. This is the gaseous state of water, known as water vapor or steam.The phase diagram of water also contains lines and points that represent the boundaries between these regions:1. Solid-liquid boundary Melting line : This line separates the solid and liquid regions and represents the conditions under which ice melts into water or water freezes into ice. The melting/freezing point of water at standard atmospheric pressure 1 atm is 0C 32F .2. Liquid-gas boundary Boiling line : This line separates the liquid and gas regions and represents the conditions under which water boils into vapor or vapor condenses into water. The boiling/condensation point of water at standard atmospheric pressure 1 atm is 100C 212F .3. Solid-gas boundary Sublimation line : This line separates the solid and gas regions and represents the conditions under which ice sublimates into vapor or vapor deposits into ice, without passing through the liquid phase.4. Triple point: This is a unique point on the phase diagram where all three states of matter solid, liquid, and gas coexist in equilibrium. For water, the triple point occurs at a temperature of 0.01C 32.018F and a pressure of 611.657 Pa 0.00604 atm .5. Critical point: This is the point at which the distinction between the liquid and gas phases disappears, and they become indistinguishable. For water, the critical point occurs at a temperature of 374.12C 705.4F and a pressure of 22.064 MPa 217.75 atm .Understanding the phase diagram of water helps us predict the state of water under different temperature and pressure conditions and is crucial for various scientific and industrial applications.