Hydrocarbons: compare question

In an industrial process, hexane is cracked to form a mixture that includes ethene.

(a) State the conditions required for the cracking of hexane, and write an equation for the formation of ethene from hexane. (b) Ethene can also be produced by the dehydration of ethanol. State the reagent and conditions used for this dehydration. (c) The ethene produced is then converted into a polymer. State the type of polymerisation and give the repeating unit of the polymer formed from ethene. (d) A different alkene, with the molecular formula $\ce{C5H10}$, is oxidised by hot concentrated acidified $\ce{KMnO4}$. The products are propanone and ethanoic acid. Use this information to deduce the structural formula of the alkene. Explain your reasoning.