Consider a real gas placed in a container. If the intermolecular attractions are supposed to disappear suddenly which of the following would happen? (a) The pressure decreases (b) The pressure increases (c) The pressure remains unchanged (d) The gas collapses

When we discuss gases in chemistry, we often start with an idealized model, the 'ideal gas', which assumes no intermolecular forces and that the molecules occupy no volume. However, the behavior of 'real gases' deviates from this simple model due to the presence of intermolecular attractions and the finite volume of the molecules.

For instance, under high pressure, the volume of the gas molecules becomes significant, and the pressure is less than what would be predicted by the ideal gas law. Conversely, at high temperatures or low pressures, where the molecules are far apart, intermolecular forces become negligible, and the gas behaves more ideally. These deviations are described by the van der Waals equation, which adjusts for the presence of these forces and molecular volume.

Understanding real gas behavior is crucial for students preparing for competitive exams like the Joint Entrance Examination (JEE) for engineering in India, which often includes questions on thermodynamics and physical chemistry. This knowledge is not only vital for solving complex problems but also for grasping practical scenarios in industrial and environmental chemistry.

Physical chemistry bridges the gap between the physical principles governing molecules and how that manifests in chemical systems. For JEE aspirants, it's a challenging yet rewarding subject as it involves the application of concepts like thermodynamics, kinetics, and equilibrium to solve complex chemical problems.

Topics like real gas behavior and pressure changes in gases are often tested because they demonstrate a student's ability to apply scientific principles to theoretical and practical situations. To excel, students must comprehend the mathematical relationships described by laws such as the ideal gas law and the van der Waals equation, and be able to apply them to situations where gases do not behave ideally. This demands a firm understanding of the principles, as well as extensive practice with problems and conceptual questions, like those involving the sudden disappearance of intermolecular attractions within a gas.

The pressure exerted by a gas is a result of the collisions of its molecules with the walls of its container. Changes in conditions such as temperature, volume, and the presence or absence of intermolecular forces can significantly impact the pressure of a gas.

In scenarios where intermolecular attractions disappear, as in our exercise example, the frequency and force of the molecules' collisions with the container walls increase, leading to an increase in pressure. This is a straightforward application of kinetic molecular theory, which helps us relate the macroscopic properties of gases, such as pressure, to the microscopic actions of their molecules.

Pressure changes are also essential in understanding natural phenomena such as weather patterns and the behavior of gases in various chemical processes. Hence, knowledge of how pressure can alter with changes in molecular interactions is fundamental for any student of chemistry.