Question

Can you please explain why

For each compound below, circle the letter which corresponds to the best description of its reactivity in electrophilic aromatic substitution (a) More reactive than Ph-OMe (b) More reactive than Ph-O-CO-Me but less than PhoMe (c) More reactive than Ph-H but less than PhO-CO-Me (d) Less reactive than Ph-H but more than Ph-CO2H (e) Less reactive than Ph-CO2H a a b b c c d d e e 16. 17. 18. 19. Ph-NH2 is Ph-N"Mez is Ph-NH-CO-CH3 is Ph-CH2CH2CH2CH3 is Ph-OH is Ph-CH3 is Ph-NO2 is a a a b b b c c c d d d e e e

Answer 1

> Table - ÖM, > -ÖH > - Öch, > - NH-8-cm > -o-8-cny scene | 1 - CH₂ CH Chacha > -H > - cool >- No . > -Nimez Above is order of reactivity in electrophilic aromatic substition. Mechanism of electrophilic cromatic substition and Areniumion First step is of aromaticity in would be reactivity. . First step is slowest on rate determining step as I there is loss of aromaticity in it. Hence, more stable in arenium ion, more would be reactivity. Therefore, we can say, more is electron doroting ability, more is reactivity towards electrophilic aromatic substition. In this way table ® is prepared based on election doneting ability of various groups. 6. Pha NHL is @ beide @ is conect Phrnt i most reactive among all groups mentioned in this questioni -The donates election by tri resonance effect. [see table ☺ ]. w Phan Nimez is a b c d @ } @ is comect I purames would be least reactive positive change

GA on nitrogen will cause highly - I effective (inductie effect) which will highly destabilize arenium ion. Ph- amen is the most deactivity group among all giver groups in question. [see table ®] 12]. -NH-enemy is a Ⓡedel ☺ is correct paccm s. 1-cm H 23-2-1-eng, hot om mense wat nation a nd co-cn - Elu220 cmą - Cross conjugation Due to cross-conjugation , phrink-encha is less electron donating than Phnome.. But & amų cho is more stable than Solucra as nitrogen is less electronegative than oxy Hence, phanh-dehy is more electron. donating group than phrion E-cha.. 15 phacronzen.ch [a b® de ☺ is comect - cha cha cha donetes electron using inductive effect / +I and hapesconjugation effect. While ronden group donates electron us te / mesomesic/resonace effect : Since, mesomeric / resonance effect is stronger than inductive effect. phaer criarache

is lessen reactive than phrond-cha but more reactive than pham. [20] Ph-oh is @ b c de Answer is ②. & ( Due to steric effect of 1. Z methyl on oxygen, resonance Phenol Anisole is little bit hindered in anisole. Hence, resonance effect is more stronger in phenol. Hence, Ph-oh donates electrons more effectively than ph-ocha. Therefore, Ph-on is more reactive them Phrocha. E 21 ph-cha is [a bo d e] ☺ is comect 3 group show, electron donation through resonance effect . While Phacha has electron donation through inductive and hyper conjugative effect. Since, res resonance effects inductine effet Hence, Ph-on Erectly is more reactive than ph-chiz. (22.] pu No, is labed @ 7 ® es conect pundi-on pn-Q 50 strongly deactivating due to positive change on nihagen I one to cross atom. conjugation, it's ar effect is weakened

17 ¿-OH @linn 7. Electon withdraw through resonance effect cross-conjugation ses trict election withdrewing effect reactive than Ph.no, son 3 is more YAME Hence, Ph-cool