1559T_ch02.18-3710/22/051:11Page26 EQA 26.chapter 2 STRUCTURE AND REACTIVITY ()CH.CO0 CH.COOH2 dqe+naC+Ne太=1o K=5.0×10-7 24.(a)CN-is a Lewis base (b)CHOH is a Lewis base (e)(CHa)CH*is a Lewis acid (d)MgBra is a Lewis acid (e)CH BH,is a Lewis acid (f)CHS is a Lewis bas atom have ben left out: N=C:今CH-CH,一：N=C-CH-CH, Br-Mg今：6-CH,一Br-Mg-6CH, Br H Br H H CH,-B个-CH,一CH,=B--CH H CH,CHBr (CH)CH-6-#CH,CH,-8-CH,CH,CH2- 80 CH,CH2-C.H CH,CHs-CCH.CH:CH,CH.CH 8080 80 CH- 8'CHs(c) HF
CH3COO F
CH3COOH Keq  32 stronger acid stronger base weaker base weaker acid (d) CH3 
NH3 CH4
NH2  Keq  1015 stronger base stronger acid weaker acid weaker base (e) H3O

Cl H2O
HCl Keq 5.0  107 weaker acid weaker base stronger base stronger acid (f ) CH3COOH
CH3S CH3COO
CH3SH Keq  2.0  105 stronger acid stronger base weaker base weaker acid 24. (a) CN is a Lewis base (b) CH3OH is a Lewis base (c) (CH3)2CH
is a Lewis acid (d) MgBr2 is a Lewis acid (e) CH3BH2 is a Lewis acid (f ) CH3S is a Lewis base Let’s be smart about the second part. We have three Lewis acids and three Lewis bases. So pair them up and answer the question with just three equations. To reduce clutter, the three lone pairs around each halogen atom have been left out: 25. Refer to any table of electronegativities to determine bond polarities. Butane, 2-methylpropene, 2-butyne, and methylbenzene lack polarized bonds. The other structures have the polarized bonds shown. 26. Nucleophiles: (a) and (d). Both I and S in these species contain one or more lone pairs, making them Lewis bases, capable of attacking electron-deficient atoms such as those found in Lewis acids. CH3CH2CH2 C 

N  
 O H H CH3 CH3 CH3 CH3 C 


N   
N CH3CH2 C CH2CH3 
O   O C 
 O CH3CH2 C CH3 

O   O CH3CH2 C H CH3CH2 C CH2CH2CH3 O H 

 O  O CH3CH2 C 

  O CH3CH2 Br (CH3)2CH O H CH3CH2 O CH3 CH3CH2 S H 





    Mg

CH

N C    CH3 CH3 N C CH CH3 B H H CH3 CH3 CH3 S O CH3 H Br Br Mg O
CH3 B H H CH3 S CH3 H Br Br 26 • Chapter 2 STRUCTURE AND REACTIVITY 1559T_ch02_18-37 10/22/05 1:11 Page 26