Which metals are used in the currency of the $UK$?

Identify the reaction,which is not related to the extraction of copper.

Spiegeleisen is an alloy of

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

Which of the following is correct?

Read the following statements :
$(I)$ $Al$ has greater affinity than that of $Cr$ for oxygen
$(II)$ $Al$ can be used for reduction of $Fe_2O_3$
$(III)$ Carbon is used for reduction of $PbO$
$(IV)$ $SnO_2$ can be reduced by carbon
Choose the correct set of statement$(s)$: