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

Which of the following statements is wrong?

Consider the following statements:
$(a)$ When the lead-silver alloy is rich in silver,lead is removed by the cupellation process.
$(b)$ Froth flotation can be applied for non-sulphide ores also using a suitable activator.
$(c)$ $PbSO_4 + H_2SO_4$ electrolyte is used for the refining of $Pb$ by electrolysis.
$(d)$ Any metal will not reduce the oxide of other metals which lie above it in the Ellingham diagram.
Using $'T'$ for true and $'F'$ for false statements in the given sequence,select the correct set of code.

Which of the following elements constitutes a major impurity in pig iron?

Mark the steel in which carbon percentage is highest.

The percentage $(\%)$ of silver in the alloy German silver is: