JEE Advanced2008ChemistryStates of MatterActual
A gas described by van der Waals' equation
Options
- Abehaves similar to an ideal gas in the limit of large molar volumes
- Bbehaves similar to an ideal gas in the limit of large pressures
- Cis characterised by van der Waals' coefficients that are dependent on the identity of the gas but are independ
- Dhas the pressure that is lower than the pressure exerted by the same gas behaving ideally
Correct answer
B. behaves similar to an ideal gas in the limit of large pressures
Step-by-step solution
The gas described by van der Waals' equation in the limit of large molar volume, in the intermediate range of pressure experience balancing by two factors. (p+ a V^2 )(V-b)=R T p V= a V -p b+ a b V^2 =R T (We can neglect the product of two very small constants, a b V^2 ) So, p V+ a V -p b=R T As a V =p b The gas behaves ideally, p V=R T - The van der Waals' constants ' a ' and ' b ' are characteristics of the gas. The value of these constants are determined by the critical constants of the gas a=3 p_C V_C^2=3 p_C (