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4.14 a) Remember, a stronger base is a produced from a weaker conjugate acid. the conjugate acid of is a weaker acid than H₂S, the conjugate acid of (S is beneath in the periodic table). Therefore is a stronger base than b) CH₃NH₂ is a weaker acid than because O is more electronegative than N. Thus CH₃NH⁻ is a stronger base than CH₃O⁻. 4.15 a) b) CH₃CH₂O H c) CH₃S H 4.16 a) The two electron withdrawing fluorines of CHF₂CO₂H cause a larger stabilization of the conjugate base, resulting in a stronger acid. b) CHF₂CO₂H is a stronger acid because F is more electronegative than Br and has a stronger electron withdrawing effect. c) is a stronger acid because the OCH₃ group is an electron withdrawing group compared to H. 4.17 The hydrogen bonded to the sp hybridized carbon is most acidic. CH₃CH₂C=C+H 4.18 In the resonance structures of the conjugate base of the meta isomer of nitrophenol, the electron pair is never on the carbon atom to which the nitro group is attached, so the electrons cannot be delocalized onto the oxygens of the nitro group. Thus there are fewer resonance structures and less resonance stabilization for the meta isomer than for the para isomer. :0: : : NO₂ NO₂ NO₂ NO₂ 52