Find total number of correct statement(s) related to the metal extraction processes (i) A mixture of PbS and PbO undergoes self-reduction to produce Pb and SO 2 . (ii) Liquation method is used for t

Question

Find total number of correct statement(s) related to the metal extraction processes

(i) A mixture of PbS and PbO undergoes self-reduction to produce Pb and $SO_{2}$ .

(ii) Liquation method is used for the refining of metals having high melting point and are associated with low melting impurities.

(iii) Partial oxidation of sulphide ore of copper by roasting, followed by self-reduction produces blister copper.

(iv) In cyanide process, zinc powder is utilized to precipitate gold from $Na [Au (CN)_{2}]$

(v) Refining of blister copper is done by carbon reduction

TestHub · Accepted Answer

Statements (i), (iii), and (iv) are correct.

(i) PbS and PbO undergo self-reduction: $2 P b S + 3 O_{2} \to 2 P b O + 2 S O_{2}$ ; $P b S + 2 P b O \to 3 P b + S O_{2}$ .

(iii) Partial roasting of Cu₂S forms Cu₂O, which then self-reduces: $2 C u_{2} S + 3 O_{2} \to 2 C u_{2} O + 2 S O_{2}$ ; $C u_{2} S + 2 C u_{2} O \to 6 C u + S O_{2}$ .

(iv) Zinc precipitates gold: $2 N a [A u (CN)_{2}] + Z n \to N a_{2} [Z n (CN)_{4}] + 2 A u$ .

(ii) Liquation is for low melting metals with high melting impurities.

(v) Blister copper is refined by electrolytic refining.

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