Solder is an alloy of

Which alloy is used for making artifacts?

Among the following compounds,the number of those present in copper matte is $......$
$A.$ $CuCO_3$
$B.$ $Cu_2S$
$C.$ $Cu_2O$
$D.$ $FeO$

Identify the reaction,which is not related to the extraction of copper.

Spiegeleisen is an alloy of

Among statements $(a)-(d),$ the correct ones are
$(a)$ Limestone is decomposed to $CaO$ during the extraction of iron from its oxides.
$(b)$ In the extraction of silver,silver is extracted as an anionic complex.
$(c)$ Nickel is purified by Mond's process.
$(d)$ $Zr$ and $Ti$ are purified by Van Arkel method.