Final answer:
The number of moles of gas consumed and the change in pressure in a reaction vessel, at constant volume and temperature, are directly proportional.
Step-by-step explanation:
The correct relationship between the number of moles of gas consumed and the change in pressure in a reaction vessel, at constant volume (V) and temperature (T), is directly proportional. According to Avogadro's law, the volume of a gas is directly proportional to the number of moles of that gas when pressure and temperature are held constant.
Therefore, assuming the volume of the reaction vessel remains unchanged, an increase in the number of moles of gas would result in an increase in pressure, and a decrease in the number of moles of gas would correspondingly result in a decrease in pressure. This is because at constant temperature and volume, the pressure of a gas depends on the number of molecules present, as reflected in the ideal gas law: PV = nRT.