Reactions of R-X with Nucleophiles/Bases

Reactions of R-X with Nucleophiles/Bases
R in R-X	Poor nucleophile [eg H₂O]	Weakly basic, good nucleophile [eg I^-]	Strongly basic, unhindered nucleophile [eg CH₃O^-]	Strongly basic, hindered nucleophile [eg (CH₃)₃CO^-]
methyl	no rxn	S_N2	S_N2	S_N2
unhindered primary	no rxn	S_N2	S_N2	E2
branched primary	no rxn	S_N2	E2	E2
secondary	slow S_N1, E1	S_N2	E2	E2
tertiary	S_N1, E1	S_N1, E1	E2 (+ E1)	E2 (+ E1)

unhindered primary = -CH₂-CH₂-X; branched primary = -CH(R)-CH₂-X