Question

12.(a) Explain two ways by which food industries prevent rancidity.
(b) Discuss the importance of decomposition reaction in metal industry with three points.

Answer 1

Answer:

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Explanation:

(a) (i) Rancidity can be prevented by adding antioxidants to food containing

fat and oil, e.g. butylated hydroxy anisole is added to butter as antioxidant.

(ii) It can be prevented by packaging fat and oil containing foods in nitrogen gas.

(b) (i) Molten NaCl is electrolytically decomposed to form sodium metal.

(ii) Aluminium metal is obtained by electric decomposition of bauxite ore mixed with cryolite.

(iii) Carbonate ores are thermally decomposed to give metal oxide which on reduction give metal

Answer 2

Explanation: Rancidity is complete (or) incomplete oxidation (or) hydrolysis of fats and oils when exposed to air light moisture loss by bacterial action resulting in an unpleasant taste.

a) 1)  It can be presented by adding antioxidants to food containing fat and oil ex hydroxy anisole is added to butter.

    2)  It can be presented by packing fat and oil containing foods in nitrogen gas.

b) 1) Nolten Nacl is hydroelectrically decomposed to form sodium metal.

    2) aluminum metal is obtained by electric decomposition of bauxite (or) mixed with Cryolite

   3) Carbonateores are thermally decomposed to give metal oxide which on reduction give metal.