Solder is an alloy of

Percentage of silver in German silver is (in $\%$)

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.

Which among the following statement$(s)$ is(are) true for the extraction of aluminium from bauxite?
$A$. Hydrated $Al_2O_3$ precipitates,when $CO_2$ is bubbled through a solution of sodium aluminate.
$B$. Addition of $Na_3AlF_6$ lowers the melting point of alumina.
$C$. $CO_2$ is evolved at the anode during electrolysis.
$D$. The cathode is a steel vessel with a lining of carbon.

The alloy,which contains $95 \%$ aluminium and small amounts of copper,magnesium and manganese is . . . . . .

Match the alloys in Column $A$ with their uses in Column $B$:

Column $A$	Column $B$
$(1)$ Stainless steel	$(a)$ Riveting
$(2)$ Bronze	$(b)$ Making artifacts
$(3)$ Nitinol	$(c)$ Making coins
$(4)$ German silver	$(d)$ Making musical instruments
	$(e)$ Making surgical instruments