Question

What is reduced pressure in thermodynamics?

Answer 1

Hint:This question is based on the thermodynamic concepts of reduced properties of a fluid. These reduced properties are obtained by the division of the original parameters of temperature, pressure and volume by the corresponding critical parameters of a fluid.

Complete step by step answer:
The reduced properties of a fluid are a set of state variables that are scaled by the fluid's state properties at its critical point in thermodynamics. The simplest form of the theorem of comparable states is based on these dimensionless thermodynamic coordinates combined with a substance's compressibility factor.The reduced pressure can be written as:
$p_r =\dfrac{p}{p_c}$
Here, $p$ is the reduced pressure, $p_r$ is the reduced pressure and $p_c$ is the critical pressure.

The critical pressure of a substance is the pressure that corresponds to the substance's critical point (or critical state). A material's critical point is defined as the temperature and pressure range at which a liquid substance can coexist with its vapour.

Any amount of pressure applied to a substance at temperatures above its critical temperature will not cause it to liquefy. The pressure that must be applied to a substance in order for it to liquify at its critical temperature can thus be described as the critical temperature of that substance. The symbol '$p_c$' is frequently used to represent a substance's critical pressure.

Note:The molecules of a substance with kinetic energy greater than their critical temperature are known to have too much kinetic energy for intermolecular forces of attraction to bind them together in the liquid phase. As a result, the substance cannot liquefy above the critical temperature.