Which compound in each of the following pairs is more reactive in S_N2 reaction

with OH^-?

(i) CH₃Br or CH₃I (ii) (CH₃)₃CCl or CH₃Cl

Predict all the alkenes that would be formed by dehydrohalogenation of the

following halides with sodium ethoxide in ethanol and identify the major alkene:

(i) 1-Bromo-1-methylcyclohexane

(ii) 2-Chloro-2-methylbutane

(iii) 2,2,3-Trimethyl-3-bromopentane.