Write a note on the following reactions.
Dehydration of ethanol

Explanation

Preparation of alkene by dehydration of alcohol :
When an alcohol is heated at `430-440K` with excess of concentrated sulphuric acid, a molecule of water from alcohol is removed and an alkene is formed. This reaction is called elimination reaction.
`underset("Ethanol")(C_(2)H_(5)OH)overset("Conc."H_(2)SO_(4))underset(430-440K)(to)underset("Ethene")(CH_(2)=CH_(2))`
Ethene can also be prepared in laboratory by catalytic dehydration of alcohol.
`underset("Ethanol")(C_(2)H_(5)OH)overset(Al_(2)O_(3))underset(623-723K)(to)underset("Ethene")(CH_(2)=CH_(2))`