A、含有3个碳原子的烷基为丙基、异丙基两种,甲苯苯环上有3种氢原子,分别处于甲基的邻、间、对位位置上,所以甲苯苯环上的一个氢原子被含3个碳原子的烷基取代,同分异构体最多有3×2=6种,故A错误;
B、两个苯环通过单键相连,可以看作甲基取代苯环上的H原子,分子中有3种H原子,有3种结构(含本身),两个苯环可以通过-CH
2-连接有1种结构,故其同分异构体共有3+1-1=3种,故B错误;
C、戊烷的同分异构体有CH
3-CH
2-CH
2-CH
2-CH
3、
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/5ab5c9ea15ce36d302a5c98139f33a87e850b1da?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
、
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/9213b07eca806538ea4beea294dda144ac3482da?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
,
若为CH
3-CH
2-CH
2-CH
2-CH
3,一氯代物有:CH
3CH
2CH
2CH
2CH
2Cl;CH
3CH
2CH
2CHClCH
3;CH
3CH
2CHClCH
2CH
3;
若为
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/5ab5c9ea15ce36d302a5c98139f33a87e850b1da?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
,一氯代物有:CH
3CH(CH
3)CH
2CH
2Cl;CH
3CH(CH
3)CHClCH
3;CH
3CCl(CH
3)CH
2CH
3;CH
2ClCH(CH
3)CH
2CH
3;
若为
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/9213b07eca806538ea4beea294dda144ac3482da?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
,一溴代物为:CH
2C(CH
3)
2CH
2Cl,故一氯代物种数有3+4+1=8,故C正确;
D、苯环是平面正六边形,菲具有很高的对称性,沿如图虚线对称
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/0b55b319ebc4b7454f266ca7ccfc1e178b8215d4?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
,有如图所示5种H原子,故菲的一硝基取代物有5种,故D正确;
故选CD.