The following statements about isomers of organic compounds are incorrect: () A. Isomers with molecular formula C4H8 share (regardless of stereoisomerism) 5.

A. Isomers with molecular formula C4H8 may be olefins: CH2═CH-CH2CH3, CH3CH=CHCH3, CH2=C(CH3)2, or cycloalkanes: cyclobutane and methylcyclopropane, so A is correct;

B. Chlorine atoms can occupy two vertices on the same side, two vertices on the diagonal of the same plane and two vertices on the diagonal of a cube, so there are three kinds of dichlorides in cubic alkanes, and the types of hexachlorinated compounds are equal to three kinds of dichlorides, so b is correct;

C isomers with molecular formula C5H 12O belong to alcohols, and the possible structures of pentyl -C5H 1 1 are: -CH2CH2CH2CH2CH3, -CH(CH3)CH2CH2CH3, -CH(CH2CH3)2, -CHCH(CH3)CH2CH3.

D contains four hydrogen atoms, so there are four monobromides, so D is correct;

So choose C.