Extraction of Metals - Result Question 90
93. Each of the following statement is true, only under some specific conditions. Write the condition for each subquestion in not more than 2 sentences.
(i) Metals can be recovered from their ores by chemical methods
(ii) High purity metals can be obtained by zone refining method.
(1984, 2M)
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Solution:
- (i) If the metal is moderately electropositive, e.g. $Fe, Sn, Pb$ or $Cu$, they can be obtained from their ore by chemical reduction methods.
However, if the metal is highly electropositive, e.g. $Al, Mg$ etc., no reducing agent exist for reduction of their ions $\left(Al^{3+}, Mg^{2+}\right)$ and they are obtained by electrolytic reduction of their molten salt.
(ii) Metals like $Ge$ is required in high purity, can be readily melted and can easily crystallise out from the melt form.
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