Question

Which of the following statement(s) is (are) true ?

• A. In process of the precipitation of silver sodium dicyano argentate (l), the zinc acts as reducing agent as well as a complexing agent.
• B. In process of the roasting, the copper pyrites is converted into a mixture of $C{u}_{2}S$ and FeS which, in turn, are partially oxidised
• C. Limonite, haematite and magnesite are ores of iron.
• D. Tin and lead both are extracted from their ores by self-reduction.

Answer 1

Answer: (A), (B)

The correct options are
A In process of the precipitation of silver sodium dicyano argentate (l), the zinc acts as reducing agent as well as a complexing agent.
B In process of the roasting, the copper pyrites is converted into a mixture of $C{u}_{2}S$ and FeS which, in turn, are partially oxidised

(A) In process of the precipitation of silver sodium dicyano argentate (l), the zinc acts as reducing agent as well as a complexing agent. The oxidation state of silver changes from +1 to 0.

$2NaAg(CN{)}_2+Zn\to 2Ag+N{a}_{2}Zn(CN{)}_4$

(B) In process of the roasting, the copper pyrites is converted into a mixture of $C{u}_{2}S$ and $FeS$ which, in turn, are partially oxidised.

$2CuFe{S}_2+O_2\to C{u}_{2}S+2FeS+S{O}_{2}2C{u}_{2}S+3O_2\to 2C{u}_{2}O+2S{O}_{2}2FeS+3O_2\to 2FeO+2S{O}_2$

(C) Limonite $2F{e}_2{O}_3.3H_{2}O$ , haematite $F{e}_2{O}_3$ and magnetite $F{e}_3{O}_4$ are ores of iron. Magnesite $MgC{O}_3$ is an ore of magnesium.

(D) Tin is extracted by carbon reduction method and Lead is extracted by either air reduction process (self reduction method) or carbon reduction process.