Water typically boils at 100 degrees Celsius (212 degrees Fahrenheit) at standard atmospheric pressure, but it can boil at lower or higher temperatures depending on the pressure applied. The boiling point of a substance is the temperature at which its vapor pressure equals the atmospheric pressure.
At room temperature, the atmospheric pressure is usually around 1 atmosphere (atm). When pressure is increased, the boiling point of water also increases. This is because the higher pressure raises the vapor pressure required for the liquid to transition into a gas phase.
However, no matter how much pressure is applied, water will not boil at room temperature. This is because at standard atmospheric pressure, the vapor pressure of water is much lower than the pressure required to reach the boiling point at room temperature.
To illustrate this, consider the phase diagram of water, which shows the relationship between temperature, pressure, and the different phases of water (solid, liquid, and gas). At atmospheric pressure, the phase diagram indicates that water exists in the liquid phase at room temperature.
Increasing the pressure on water can shift its phase diagram, causing the boiling point to rise. For example, at higher pressures such as those found in pressure cookers, water can reach temperatures above 100 degrees Celsius before boiling. This allows for faster cooking times since higher temperatures accelerate the cooking process.
In summary, the reason water doesn't boil at room temperature, even with increased pressure, is because the vapor pressure of water at room temperature is lower than the pressure required for it to reach its boiling point.