The smelting of iron in the blast furnace involves all the following processes except:

What is the percentage $(\%)$ of silver in German silver?

Which of the following is not correctly matched?

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.

Explain the following:
$(a)$ $CO_2$ is a better reducing agent below $710 \ K$ whereas $CO$ is a better reducing agent above $710 \ K$.
$(b)$ Generally,sulphide ores are converted into oxides before reduction.
$(c)$ Silica $(SiO_2)$ is added to the sulphide ore of copper in the reverberatory furnace.
$(d)$ Carbon and hydrogen are not used as reducing agents at high temperatures for certain metals.
$(e)$ Vapour phase refining method is used for the purification of $Ti$.

List-$I$ contains different compounds formed during the extraction of metal $(M)$ in List-$II$. Match the compounds in List-$I$ with the corresponding metal and process in List-$II$.

List-$I$	List-$II$
$(P). [M(CN)_2]^-$	$(1). Ni$ (during refining of metal)
$(Q). [M(CO)_4]$	$(2). Ti$ (during refining of metal)
$(R). MI_4$	$(3). Pb$ (during roasting of ore)
$(S). MO$	$(4). Ag$ (during leaching of ore)