JEE Main · 2020 · 04 Sep 2020 · Shift 1 · Alcohols Phenols and Ethers

When neopentyl alcohol, $(\mathrm{CH}{}_3){}_3\mathrm{C}-\mathrm{CH}{}_2\mathrm{OH}$, is heated with acid it loses water to give a primary carbocation, which at once rearranges by a $1,2$-methyl shift to the more stable tertiary carbocation. Loss of a proton then gives two alkenes: the major one (about $85\%$) is the more substituted, more stable $2$-methylbut-2-ene, following Zaitsev's rule, and the minor one (about $15\%$) is $2$-methylbut-1-ene. These are the two alkenes formed.