Refractory materials are generally used in furnaces because

Given below are two statements.
Statement $I$: Pig iron is obtained by heating cast iron with scrap iron.
Statement $II$: Pig iron has a relatively lower carbon content than that of cast iron.
In the light of the above statements,choose the correct answer from the options given below.

Give the correct order of initials $T$ or $F$ for following statements. Use $T$ if statement is true and $F$ if it is false.
$(i)$ In Goldschmidt thermite process,aluminium acts as a reducing agent.
$(ii)$ $Mg$ is extracted by electrolysis of aqueous solution of $MgCl_2$.
$(iii)$ Extraction of $Pb$ is possible by carbon reduction method.
$(iv)$ Red Bauxite is purified by Serpeck's process.

Select the incorrect statement.

German silver is an alloy of

Which alloy contains $Cu$,$Sn$,and $Zn$?