Answer:
mol·L⁻¹·s⁻¹
Explanation:
In the case of a zero-order reaction, the reaction rate does not change with the decrease or increase in the concentrations of the reactants:
And because the rate must have units of mol·L⁻¹·s⁻¹, then the rate constant k must also have units of mol·L⁻¹·s⁻¹.