What happens when
(i) ethanol burns in air.
(ii) ethanol reacts with sodium metal.
(iii) ethanol is oxidised with chromic anhydride in glacial ethanoic acid.
(iv) ethanol is heated with alkaline potassium permanganate.
(v) ethanol is heated with ethanoic acid in the presence of a few drops of concentrated sulphuric acid?

Explanation

(i) Ethanol is highly inflammable liquid. It catches fire easily and starts burning. Ethanol burns readily in air with a blue flame to form carbon dioxide and water vapour:
`C_(2)H_(5)OH+3O_(2) underset("(Burning)") overset("Combustion")to 2CO_(2)+3H_(2)O`
A lot of heat is produced during the combustion of ethanol.
(ii) Ethanol reacts with sodium to produce sodium ethoxide and hydrogen gas:
`underset("Ethanol")(2C_(2)H_(5)OH)+2Na to underset("Sodium ethoxide")(2C_(2)H_(5)ONa)+H_(2)`
(iii) When ethanol is treated with chromic anhydride, then its partial oxidation takes place and ethanal is formed.
`underset("Ethanol")(CH_(3)CH_(2)OH) underset(CH_(3)COOH)overset(CrO_(3)" in")to underset("Ethanal")(CH_(3)CHO)`
Chromic anhydride oxidises ethanol to ethanal.
(iv) Alkaline `KMnO_(4)` oxidises ethanol to ethanoic acid.
`underset("Ethanol")(CH_(3)CH_(2)OH) overset("Alk. "KMnO_(4))to underset("Ethanoic acid")(CH_(3)COOH)`
(v) Ethanol reacts with ethanoic acid in presence of concentrated sulphuric acid to form a sweet smelling ester, ethyl ethanoate.
`underset("Ethanol")(C_(2)H_(5)OH)+underset("Ethanoic acid")(CH_(3)COOH) overset(H_(2)SO_(4))to underset("Ethyl ethanoate")(CH_(3)COOC_(2)H_(5))+H_(2)O`