Which metals are used in the currency of the $UK$?

Which alloy contains $Cu$ and $Zn$?

Match Column-$I$ with Column-$II$.

Column-$I$	Column-$II$
$P$. Nitriding	$I$. Process of heating steel to redness and then cooling it very slowly
$Q$. Annealing	$II$. Process of heating steel in presence of $NH_3$ and producing hard coating of Iron Nitride on the surface of steel
$R$. Tempering	$III$. Process of heating steel to redness and then cooling it suddenly by plunging it into water or oil
$S$. Quenching	$IV$. Process of heating quenched steel to a temperature well below redness and then cooling it slowly

To obtain steel entirely free from sulphur and phosphorus,the process used is

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

The correct statement$(s)$ related to processes involved in the extraction of metals is(are):
$(A)$ Roasting of Malachite produces Cuprite.
$(B)$ Calcination of Calamine produces Zincite.
$(C)$ Copper pyrites is heated with silica in a reverberatory furnace to remove iron.
$(D)$ Impure silver is treated with aqueous $KCN$ in the presence of oxygen followed by reduction with zinc metal.