In the leaching of $Ag_2S$ with $NaCN$,a stream of air is also passed. This is because of:

Match the conversions in Column-$I$ with the type$(s)$ of reaction$(s)$ given in Column-$II$.

Column-$I$	Column-$II$
$A$. $PbS \rightarrow PbO$	$p$. roasting
$B$. $CaCO_3 \rightarrow CaO$	$q$. calcination
$C$. $ZnS \rightarrow Zn$	$r$. Carbon reduction
$D$. $Cu_2S \rightarrow Cu$	$s$. self reduction

The correct statements are :

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

What is the approximate ratio of roasted ore,coke and limestone respectively in the charge to be added into the blast furnace for the extraction of iron?

The correct statement$(s)$ related to the metal extraction processes is(are):
$(A)$ $A$ mixture of $PbS$ and $PbO$ undergoes self-reduction to produce $Pb$ and $SO_2$.
$(B)$ In the extraction process of copper from copper pyrites,silica is added to produce copper silicate.
$(C)$ Partial oxidation of sulphide ore of copper by roasting,followed by self-reduction produces blister copper.
$(D)$ In the cyanide process,zinc powder is utilized to precipitate gold from $Na[Au(CN)_2]$.