The reaction between hydrogen gas H2 and iodine gas I2 to form hydrogen iodide 2HI is a well-known reaction in chemistry. The overall reaction can be represented as:H2 g + I2 g 2HI g The mechanism of this reaction is a bimolecular process, which means that it involves the collision of two molecules. The reaction proceeds through the following steps:1. H2 and I2 molecules collide, and one of the H atoms in H2 forms a bond with one of the I atoms in I2, creating an intermediate species HI-I-H .2. The intermediate species breaks apart into two HI molecules.The rate constant for this reaction depends on the temperature and can be determined experimentally. The rate law for this reaction is given by:rate = k[H2][I2]where k is the rate constant, and [H2] and [I2] are the concentrations of hydrogen and iodine, respectively.This reaction can be catalyzed by the presence of certain substances, such as platinum or other transition metals. The catalyst provides an alternative reaction pathway with a lower activation energy, which increases the rate of the reaction. The catalyst does not get consumed in the reaction and can be used repeatedly.When a catalyst is added to the reaction, the rate constant k increases, leading to a faster reaction rate. This means that the formation of hydrogen iodide will occur more quickly in the presence of a catalyst compared to the uncatalyzed reaction.