(i) Ethanoic acid reacts with ethanol in the presence of concentrated sulphuric acid to produce the ester, ethyl ethanoale having a fruity smell.
(ii) Iron sulphide reacts with hydrochloric acid releasing a highly toxic gas hydrogen sulphide having rotten egg smell.
(iii) A dirty green precipitate of ferrous hydroxide is formed which is insoluble in excess of NaOH solution.
(iv) Ammonia bums in air to form greenish-yellow vapours of nitric oxide.
(v) The blue crystals are changed into white powder as water is removed. Concentrated sullphuric acid takes away the water molecules and the copper sulphate becomes anhydrous.
