S2 Competes with E2 Depends on the Nature of the Substrate CH3CH2CH2CH2Br CN CH3CH2CH2CH2CN str.nuc.;wk.base 10 100%SN2 CN (CH3)3CBr CH2=C(CH3)2 30 100%E2 SN2 Competes with E2 C H3 C H2 C H2 C H2 Br C N C H3 C H2 C H2 C H2 C N 1o 100% (CH3) 3 CBr C N C H2 =C(CH3) 2 100% E2 SN2 3o str. nuc.; wk. base Depends on the Nature of the Substrate