BITSAT2022ChemistryStates of MatterActual
The given graph represents the variation of compressibility factor (Z)= p V n R T , for three real gases A, B and C . Identify the only incorrect statement.
Options
- AFor the gas A, a=0 and its dependence on p is linear at all pressure.
- BFor the gas B, b=0 and its dependence on p is linear at all pressure.
- CFor the gas C , which is typical real gas for which neither. a nor b=0 . By knowing the minima and point of th
- DAt high pressure the slope is positive for all real gases.
Correct answer
B. For the gas B, b=0 and its dependence on p is linear at all pressure.
Step-by-step solution
From the graph it is clear that, the value of ' Z ' decreases with increase of pressure. We can explain as follows on the basis of van der Waals' equation. At high pressure, when ' p ' is large, V will be small and one cannot ignore ' b ' in comparison to V . However, the team a / V^2 may be considered negligible in comparison to ' p ' in van der Waals' equation. (p+ a V^2 )(V-b)=n R Tp(V-b)=n R T p V-p b=n R T or p V n R T =1+ p b n R T or Z=1+ p b n R T Thus, Z is greater than 1. As pressure is increased (at cons