Arrange the following compounds in the decreasing order of their nucleophilicity in a polar protic solvent: (i) CH ₃ OH (ii) CH ₃ SH (iii) CH ₃ NH ₂

Step-by-step solution

Nucleophilicity depends on the polarizability, electronegativity of the donor atom, and solvation effects. In a polar protic solvent, larger atoms are less solvated by hydrogen bonding and are more polarizable, which makes them better nucleophiles. Sulfur is larger and more polarizable than both nitrogen and oxygen, making CH ₃ SH the strongest nucleophile among the given compounds. For atoms in the same period, nucleophilicity decreases as electronegativity increases because the lone pair of electrons is held more