how does an increase in pressure affect the following reaction? C2H2(g)+H2(g) C2H4(g)

An increase in pressure typically affects a reaction that involves gases, such as the one you provided: C2H2(g) + H2(g) -> C2H4(g). Let's explore how an increase in pressure could affect this reaction.

When pressure is increased, the system tries to counteract this change by favoring the reaction that reduces the number of gas molecules. In this case, the number of gas molecules decreases from left to right in the reaction: 3 molecules on the left (C2H2 + H2) and 2 molecules on the right (C2H4).

To decrease the number of gas molecules, the reaction would shift in the direction that produces fewer gas molecules. This means that the reactant side (C2H2 + H2) would be favored, and the equilibrium position would shift to the left.

In simpler terms, increasing the pressure pushes the equilibrium of the reaction towards the side with fewer gas molecules, which in this case, is the reactant side. As a result, the formation of C2H2 and H2 is favored, and the production of C2H4 is reduced.

It's important to note that pressure influences the reaction only if there are different numbers of gaseous molecules on both sides. If the number of gas molecules is the same, as in a balanced equation, changing the pressure would not affect the equilibrium.

To fully understand how pressure affects a reaction, it is necessary to consider other factors as well, such as temperature and concentration. The reaction quotient (Q) and the equilibrium constant (K) also play crucial roles in determining the reaction's behavior under various conditions.

An increase in P will shift a gaseous reaction to the side with the fewer mols (in order to occupy the lesser volume).