210ALKYNES9.3The bonds become shorter and stronger in the series as the electronegativity increases.NH3H2OHFElectronegativity:N (3.0)O (3.5)F (4.0)Bond distance (pm):N@H (101)O@H (95)F@H (92)Bond dissociation energy (kJ/mol):N@H (435)O@H (497)F@H (568)Bond dissociation energy (kcal/mol):N@H (104)O@H (119)F@H (136)9.4(b)A proton is transferred from acetylene to ethyl anion.The position of equilibrium lies to the right. Ethyl anion is a very powerful base and depro-tonates acetylene quantitatively.(c)Amide ion is not a strong enough base to remove a proton from ethylene. The equilibrium liesto the left.(d)Alcohols are stronger acids than ammonia; the position of equilibrium lies to the right.9.5(b)The desired alkyne has a methyl group and a butyl group attached to a @C>C@unit. Twoalkylations of acetylene are therefore required: one with a methyl halide, the other with a butylhalide.It does not matter whether the methyl group or the butyl group is introduced frst; the order ofsteps shown in this synthetic scheme may be inverted.(c)An ethyl group and a propyl group need to be introduced as substituents on a
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