2-Bromo-2-methylbutane is heated with $\mathrm{NaOEt}$ in ethanol. The major product is

Ethoxide is a strong, unhindered base and the tertiary halide cannot undergo SN2, so E2 occurs. Saytzeff orientation gives the trisubstituted alkene $(\mathrm{CH}{}_3){}_2\mathrm{C}=\mathrm{CH}-\mathrm{CH}{}_3$, 2-methylbut-2-ene, as the major product.