Glycerol on heating with ${\mathrm{KHSO}}_4$ forms

Identify to which type does the following complex reactions belongs to-

• dehydration of 2-methyl-2-butanol

Complete the reaction and write the name of the product.

${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH} \underset{620 \mathrm{K}}{\overset{{\mathrm{Al}}_2{\mathrm{O}}_3}{\to }} ?$

Glycerol on heating with concentrated ${\mathrm{H}}_2{\mathrm{SO}}_4$ form one mole each of formaldehyde and acetaldehyde.

Represent the union of two sets by Venn diagram for each of the following.

$X=\{x | x$ is a prime number between $80$ and $100\}$

$Y=\{y | y$ is an odd number between $90$ and $100\}$