Question

When 3,3-dimethylbutanol-2 is heated with conc. $H_{2}S{O}_4,$ the main product formed is:

• A. 2,3-Dimethylbut-1-ene
• B. 2,3-Dimethylbut-2-ene
• C. 3,3-Dimethylbut-2-ene
• D. Both cis and trans isomers are formed as major product.

Answer 1

The correct option is B 2,3-Dimethylbut-2-ene

Dehydration of alcohols requires a strong acid and is carried out at high temperatures $(100-{200}^{o}C)$. The most common strong acid used for dehydration is the concentrated sulfuric acid.
In dehydration of alcohol, Saytzeff products are major products.
Hence option (b) is correct.

Here geometrical isomer is not possible as formed alkene has same group on the terminal carbon of double bond.