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प्रश्न
Which of the following options are correct?
(i) Cast iron is obtained by remelting pig iron with scrap iron and coke using hot air blast.
(ii) In extraction of silver, silver is extracted as cationic complex.
(iii) Nickel is purified by zone refining.
(iv) Zr and Ti are purified by van Arkel method.
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उत्तर
(i) Cast iron is obtained by remelting pig iron with scrap iron and coke using hot air blast.
(iv) Zr and Ti are purified by van Arkel method.
Explanation:
Iron obtained from blast is called pig iron. It contains about 4% carbon and many impurities such as Mn, P, Si, etc. The pig iron is remelted with scrap iron. This is known as cast iron. It has slightly less carbon content (3%) and is extremely hard and brittle.
\[\ce{\underset{Impure}{Zr(s)} + 2I2 ->[870K] ZrI4(g) ->[2705K][tungsten filament] \underset{Pure}{Zr(s)} + 2I2}\]
\[\ce{Ti + 2I2 ->[530K] Ti4 ->[1700K] Ti + 2I2}\]
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