Answer: cis-1-bromo-3-tert-butylcyclohexane will react faster in E2 elimination reaction.
Explanation: The two isomers are shown in the image attached.
E2 elimination reaction is known as the anti elimination reaction. For E2 elimination reaction, the leaving group 'X' should be in anti-coplanar arrangement to the [tex]\beta-H[/tex] atom.
Between the two isomers, cis-isomer is the one where leaving group 'Br' and H-atom on [tex]\beta-carbon[/tex] are in anti-position.
Hence, cis-isomer will react faster in E2- elimination reaction.
