(i) Name the method of refining of nickel (ii) What is the role of cryolite in the extraction of aluminium ? (iii) What is the role of limestone in the extraction of iron from its oxides ?

(i) Name the method of refining of nickel (ii) What is the role of cry

1.	(i) Name the method of refining of nickel (ii) What is the role of cryolite in the extraction of aluminium ? (iii) What is the role of limestone in the extraction of iron from its oxides ?
Answer» (i) Mond process. (ii) It makes aluminium a good conductor of electricity and it lowers the fusion (M.P) temperature both from 2323 k to about 1140 K. (iii) At 1123k, limestone decomposes to form CaO and `CO_(2).` CaO act as flux and combine silica (impurity) to form calcium silicate slag. `CaCO_(3) (s)overset(1123k)(to)CaO(s) + CO_(2)(g)` `CaO(s) + SiO(s) to CaSiO_(3) " Calcium silicate (slag)"`

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(i) Name the method of refining of nickel (ii) What is the role of cryolite in the extraction of aluminium ? (iii) What is the role of limestone in the extraction of iron from its oxides ?

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