Ellingham diagrams can be drawn for which of the following?

Consider the following metallurgical processes:
$I$. Heating impure metal with $CO$ and distilling the resulting volatile carbonyl (b.p. $43 \ ^oC$) and finally decomposition at $150 \ ^oC - 200 \ ^oC$ to get the pure metal.
$II$. Heating the sulphide ore in air until a part is converted to oxide and then further heating in the absence of air to let the oxide react with unchanged metal sulphide.
$III$. Electrolysis of the molten electrolyte containing approximately equal amounts of the metal chloride and $NaCl$ to obtain the metal.
The processes used for obtaining magnesium,nickel and copper are respectively:

In the wrought iron of the iron pillar located in Delhi,what other elements are present besides iron?

Match List-$I$ with List-$II$.

List-$I$ (Industrial process)	List-$II$ (Application)
$(a)$ Haber's process	$(i)$ $HNO_{3}$ synthesis
$(b)$ Ostwald's process	$(ii)$ Aluminium extraction
$(c)$ Contact process	$(iii)$ $NH_{3}$ synthesis
$(d)$ Hall-Heroult process	$(iv)$ $H_{2}SO_{4}$ synthesis

Choose the correct answer from the options given below:

The major components of German Silver are:

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.