For the irreversible reaction between CO(g) and Cl2(g) to form COCl2(g), the rate law is Rate = k[CO — Kinetics Chemistry Question

For the irreversible reaction between CO(g) and Cl₂(g) to form COCl₂(g), the rate law is Rate = k[CO][Cl₂]. In an experiment where equimolar quantities of CO(g) and Cl₂(g) are reacted, which of the following would change linearly with reaction time?