The following reaction can proceed through both El and E2 mechanisms.

The El rate constant kEI = 1.4 × 10-4s-1 and the E2 rate constant kE2 = 1.9 × 10-4 L mol-1 s-1; 0.02 M haloalkane.
(a) What is the predominant elimination mechanism with 0.5 M NaOCH3?
(b) What is the predominant elimination mechanism with 2.0 M NaOCH3?
(c) At what concentration of base does exactly 50% of the starting material react by an El route and 50% by an E2 pathway?

CH3 CH3 CH.CH.CCI NaOcH, CHOH > C,H,CH=C(CH3)2 + C6H,CH2(-CH2 CH3