10-18 - Which SN2 reaction is faster If the atom type(row...

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1 Which S N 2 reaction is faster? + CH 3 CO 2 Na Br O O A 37 + Br Br + NaOH OH + Br - B Why? stronger conjugate acid weaker base weaker conjugate acid stronger base If the atom type (row of periodic table) changes, then nucleophilicity may not be determined by basicity. O H CH 3 C O O H O H basicity nucleophilicity 38 S H O H pK a = 16 7 S H H O H H O H CH 3 C O O H O H basicity nucleophilicity If the atom type (row of periodic table) changes, then nucleophilicity may not be determined by basicity. 39 S H O H basicity nucleophilicity Why are some species, such as H-S and I weak bases and strong nucleophiles? 40 S H O H basicity nucleophilicity Sulfur has more polarizable electrons (3s/p) and can form strong bonds at long distances. O H X C R R R HO C R R R X weak bond in transition state b lf i l i bl 41 S H X C R R R HS C R R R X because sulfur is more polarizable a stronger bond is formed in the transition state O H HO C R R R Cl Cl C R R R 42 HS C R R R Cl Cl C R R R S H
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