11.4HBr+O₂→2Br₂+2H₂O之反應機構如下：
(1)HBr+O₂→HOOBr(慢)
(2)HOOBr+HBr→2HOBr(快)
(3)HOBr+HBr→Br₂+H₂O(快)
則其反應速率式為：
(A)R=k[HBr]⁴[O₂]
(B)R=k[HOOBr][HBr]
(C)R=k[HBr][O₂]
(D)R=k[HOBr][HBr]

解題關鍵：反應速率由慢速步驟決定（也稱...