Which of the following option are correct?
(i) Cast iron is obtained by remelting pig iron with scrap iron and coke using hot air blast.
(ii) In the extraction of silver, silver is extracted as cationic complex.
(iii) Nickel is purified by zone refining.
(iv) and are purified by van Arkel method
The answer is the option (i, iv) Iron obtained from blast containing about 4% carbon and many impurities such as Mn, P, Si, etc is called pig iron. It is remelted with scrap iron to obtain cast iron which has slightly less carbon content (3%) compared to pig iron and is extremely hard and brittle.
For refining of Van Arkel method based on the thermal decomposition of metal components is used. In this method, the impurities i.e. oxygen and nitrogen are removed by heating metal in an evacuated vessel with iodine.
Zone refining is used for semiconductors like Ge, Si. For purification of Nickel, Mond’s process is used.