Imagine that the reaction 2 co (g) + o2 (g) --> 2 co2 (g) occurs in a container that has a piston that moves to maintain a constant pressure when the reaction occurs at constant temperature. which of the following statements describes how the volume if the container changes due to the reaction

a.) volume increases by 50%
b.) volume increases by 33%
c.) volume remains constant
d.) volume decreases by 33%
e.) volume decreases by 50%