What is the product formed when $1$-butene is heated with $Al_2(SO_4)_3$ at $500 \ K$?

Dehydration of ethanol gives

Compound $X$ on reaction with $O_{3}$ followed by $Zn/H_{2}O$ gives formaldehyde and $2-$methylpropanal as products. The compound $X$ is :

Glycol on treatment with $PI_3$ mainly gives -

$A$ hydrocarbon having molecular formula $C_5H_{10}$ produced a tertiary alcohol upon treatment with a few drops of conc. sulphuric acid and water. The same hydrocarbon when reacted with acidic potassium permanganate produced a ketone and a carboxylic acid. The hydrocarbon is $....$

An alkene,on ozonolysis,gives formaldehyde and acetaldehyde. The alkene is: