Which among the following is an alloy of antimony,tin and copper?

Which of the following methods are not used to refine any metal?
$A$. Liquation $B$. Calcination $C$. Electrolysis $D$. Leaching $E$. Distillation
Choose the correct answer from the options given below.

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

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

For the following statements,mark $T$ for true and $F$ for false statement.
Statement $1$: $SnO_2 +$ wolframite,in this $SnO_2$ is magnetic while wolframite is non-magnetic in nature.
Statement $2$: Argentite ore is concentrated by froth floatation method.
Statement $3$: Copper and lead ores are reduced by self-reduction method.
Statement $4$: In metallurgy of $Fe$,$CO$ is used as a reducing agent at low temperature.

Identify the metal which is not common to German silver and brass.