Which metal is refined by Mond process?

In the electrolytic refining of copper,$Ag$ and $Au$ are found

During the refining of copper,the methane gas produced acts as a reducing agent. What is its specific role?

The formation of $Ni(CO)_4$ and its subsequent decomposition into $Ni$ and $CO$ forms the basis of the Mond process.
$Ni + 4CO$ $\xrightarrow{T_1} Ni(CO)_4$ $\xrightarrow{T_2} Ni + 4CO$
What are the values of $T_1$ and $T_2$?

During the purification of an impure metal by electrolysis,the impure metal is used as the ...... and the pure metal is used as the ...... .

Which of the following pairs is correctly matched?