Question

Boyle’s temperature or Boyle point is the temperature at which a real gas starts behaving like an ideal gas over a particular range of pressure. $A$ graph is plotted between compressibility factor $Z$ and pressure $P$.

What is the deviation of real gas from ideal behaviour in terms of compressibility factor, $Z$?

• A. As the temperature increases, $Z$ approaches a value close to one and gas starts behaving ideally.
• B. $Z$ continuously decreases with increase in pressure.
• C. $Z$ continuously increases with increase in pressure.
• D. At high pressure, every gas has value $Z=1$.

Answer 1

Answer: (A)

Compressibility factor $Z$ is a correction factor which gives the deviation of a real gas from an ideal gas. It is the ratio of the molar volume of a gas to the molar volume of an ideal gas, at same $T$ and $P$. Here as the temperature increases, $Z$ starts approaching towards one and then the gas starts behaving ideally.