What happens to equilibrium when pressure is increased in a gaseous system?

When pressure is increased in a gaseous system, the equilibrium shifts towards the side with fewer gas molecules.

In a gaseous system, an increase in pressure is typically achieved by decreasing the volume of the system. According to Le Chatelier's Principle, the system will respond to this change by shifting the equilibrium to counteract the change. In this case, the equilibrium will shift towards the side of the reaction with fewer gas molecules to decrease the pressure.

Consider a hypothetical reaction where A and B are gases:

A(g) ⇌ 2B(g)

In this reaction, one mole of A produces two moles of B. If the pressure is increased, the system will try to reduce the pressure. It can do this by shifting the equilibrium to the left, where there are fewer gas molecules. This is because fewer gas molecules occupy less volume, resulting in a decrease in pressure.

It's important to note that this shift in equilibrium is not permanent. If the pressure is decreased again (by increasing the volume), the equilibrium will shift back towards the side with more gas molecules. This is again in line with Le Chatelier's Principle, which states that a system at equilibrium will respond to a change in conditions by shifting the equilibrium to counteract the change.

In summary, an increase in pressure in a gaseous system will cause the equilibrium to shift towards the side with fewer gas molecules. This is a direct consequence of Le Chatelier's Principle and is a fundamental concept in the study of chemical equilibria. Understanding this principle can help you predict how changes in pressure will affect the position of equilibrium in a gaseous system.