Chapter 6.8, Problem 6.23E

(a)

Interpretation Introduction

Interpretation:The better nucleophile from ${\text{CH}}_{\text{3}}\text{SH}$ & ${\text{CH}}_{\text{3}}\text{SeH}$ should be selected.

Concept introduction:Nucleophile is an electron rich, negative ion or a molecule with an electronegative atom & lone pairs of electrons.

(b)

Interpretation Introduction

Interpretation: The better nucleophile out of ${{\text{(CH}}_{\text{3}}\text{)}}_{\text{2}}\text{NH}$ & ${{\text{(CH}}_{\text{3}}\text{)}}_{\text{2}}\text{PH}$ should be selected.

Concept introduction: Nucleophile is an electron rich, negative ion or a molecule with an electronegative atom & lone pairs of electrons.