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c) The phenyl group can stabilize a positive charge on the adjacent carbon by resonance. H H + E E + 17.4 a) The electronegative fluorines make the CF₃ an inductive electron withdrawing group. b) The positive nitrogen is an inductive electron withdrawing group. 17.5 a) Because of the unshared electrons on the S, this is an activating group and it directs ortho and para. b) The S is electron deficient, much like the carbon of a carbonyl group, so this is a deactivating group and it directs meta. c) The carbon is electron deficient, so this is a deactivating group and it directs meta. 17.6 NO₂ Br Br NO₂ a) b) + NO₂ NO₂ 17.7 a) Both groups are directing to the same position, ortho to CH₂CH₃ the ethyl group and meta to the nitro group. NO₂ 248