Understanding the Critical Temperature of Water

The critical temperature is a fundamental property of a substance. It represents the temperature above which the substance cannot exist in a liquid state, regardless of how much pressure is applied. Above the critical temperature and critical pressure, the substance enters a supercritical fluid phase, which has properties intermediate between those of a gas and a liquid.

For water, the critical temperature is a specific value that is important in various scientific and engineering applications.

Critical Temperature Value for Water

The internationally accepted value for the critical temperature of water is approximately 374.15 degrees Celsius or 647.1 K (Kelvin). This is also equivalent to 705.47 degrees Fahrenheit.

• Below the critical temperature, it is possible to condense water vapor into liquid water by applying sufficient pressure.
• At or above the critical temperature, water exists as a supercritical fluid at pressures above the critical pressure.

Analyzing the Options

Let's look at the given options in degrees Celsius:

• 273: This is close to the freezing point of water (0°C or 273.15 K), not the critical temperature.
• 374.15: This value matches the accepted critical temperature of water in degrees Celsius.
• 273.15: This is the freezing point of water in Kelvin (0°C).
• 100: This is the boiling point of water at standard atmospheric pressure (1 atm), not the critical temperature.

Based on the definition and known properties of water, the critical temperature of water in degrees Celsius is 374.15.