烷烃 CnH(2n+2)烯烃 CnH(2n)苯 C6H6醇 CnH(2n+2)O(m)酚 CnH2n-6(n≥6)O(m)醛 CnH(2n)O(m)羧酸 CnH(2n)O(2m)酯 CnH(2n)O(2m)鉴别：通入HBr,明显褪色则有烯烃；加入I2和浓硝酸,褪色则有苯；加入滴加了指示剂的碱,变中...