The reaction between hydrogen gas and iodine vapor to form hydrogen iodide is given by the chemical equation:H2 g + I2 g 2HI g This is a reversible reaction, and its rate can be affected by changes in pressure. To understand how an increase in pressure affects the rate of this reaction, we need to consider Le Chatelier's principle. Le Chatelier's principle states that if a system at equilibrium is subjected to a change in pressure, temperature, or concentration of reactants/products, the system will adjust itself to counteract the change and restore a new equilibrium.In this case, we are looking at the effect of an increase in pressure on the reaction. When the pressure is increased, the system will try to counteract the change by shifting the equilibrium position to the side with fewer moles of gas, as this will result in a decrease in the overall pressure.Looking at the chemical equation:H2 g + I2 g 2HI g On the left side reactants of the equation, there are 1 mole of H2 and 1 mole of I2, totaling 2 moles of gas. On the right side products of the equation, there are 2 moles of HI. Both sides of the equation have the same number of moles of gas.Since the number of moles of gas is the same on both sides of the equation, an increase in pressure will not cause a significant shift in the equilibrium position. Therefore, the rate of the reaction between hydrogen gas and iodine vapor will not be significantly affected by an increase in pressure.