_________ of a substance is the temperature and pressure at which three phases (gas, liquid, and solid) of the substance may coexist in thermodynamic equilibrium.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. Triple-point.
The triple point of a substance is the temperature and pressure at which all three phases—gas, liquid, and solid—can coexist in thermodynamic equilibrium. At this unique point, the properties of the phases are in balance, allowing them to exist simultaneously without any phase transitioning into another. The triple point is a critical concept in thermodynamics and is specific to each substance. For instance, the triple point of water occurs at a temperature of 0.01 degrees Celsius and a pressure of 611.657 pascals. This concept is essential for understanding phase diagrams and the behavior of materials under varying conditions.