A student studying the decomposition of hydrogen peroxide noticed that the rate at which oxygen gas collected was noticably slower after the reaction had been running for several minutes than it was when the reaction was first started. Select the best answer from the list of statements. a. The lower rate of oxygen collection is likely due to an error in making the measurement. There is no reason for the rate to be different than it was at the beginning of the reaction. b. After the reaction has been running for several minutes the concentration of hydrogen peroxide will be lower because it is being decomposed. This lower concentration is the reason the rate of oxygen production is slower. c. The lower rate of oxygen collection is likely due to a change in atmospheric pressure during the experiment. Oxygen is a gas and the volume of a gas depends on atmospheric pressure. d. After the reaction has been running for several minutes the concentration of the catalyst will be lower because it is being used up. This lower concentration is the reason the rate of oxygen production is slower.