Test site: benzene structure special topic: basic analysis of organic chemistry: a. If benzene has an alternating structure of single and double bonds, there are two ortho-disubstituted groups; B No matter whether the six carbon-carbon bonds in benzene are completely equivalent or the structure of alternating single and double bonds, there is only one single substituent of benzene; C substances containing double bonds can discolor acidic potassium permanganate; D the bond lengths of carbon-carbon single bonds and carbon-carbon double bonds are different. A. If benzene has an alternating structure of single and double bonds, there are two ortho-disubstituted groups and only one ortho-disubstituted group, which means that the six carbon-carbon bonds in benzene are completely equivalent, so A is correct; B. No matter whether the six carbon-carbon bonds in benzene are completely equivalent or the structure of alternating single and double bonds, there is only one single substituent of benzene, which cannot be proved, so B is wrong; C. substances containing double bonds can make acidic potassium permanganate fade, while benzene can't make acidic potassium permanganate solution fade, indicating that there is no double bond, so c is correct; D. The six carbon-carbon bonds in benzene molecule are completely equal in length, which proves that the six carbon-carbon bonds in benzene are completely equivalent, so d is correct; So choose: B. Comments: This topic examines the structure and properties of benzene. The topic is not difficult, and students are required to be familiar with the structural characteristics and properties of organobenzene.