Final answer:
The rate of change in the concentration of Cl₂ is equal to its rate of disappearance, which is -22.92 × 10⁻⁶ m/s, given the stoichiometry of 1:1 for Cl₂ in the reaction.
Step-by-step explanation:
The student has asked about the rate of change in [Cl₂] in a chemical reaction given that the rate of disappearance of Cl₂ at 298 K is -22.92 × 10⁻⁶ m/s. Without the stoichiometry of the reaction, we cannot determine the exact rate of change in [Cl₂]. However, if we assume a stoichiometry of 1:1 for Cl₂, then the rate of change would be equal to the rate of disappearance. Therefore, the correct answer is (b) -22.92 × 10⁻⁶ m/s, which represents the rate of disappearance (decrease) of [Cl₂].