(N/A) Prevention of corrosion is of prime importance. The damage caused by corrosion is as follows:
$I$. Metal wastage leads to significant economic losses.
$II$. Corrosion of structural components like bridges can lead to structural failure and accidents.
$III$. Corrosion in machinery reduces efficiency,causes malfunctions,and eventually leads to complete failure.
Different methods to prevent metal corrosion:
$I$. Coating the surface with paint or protective films.
$II$. Applying chemical inhibitors like bisphenol.
$III$. Coating the surface with other metals ($Sn, Zn$,etc.) that are either inert or act as sacrificial anodes. An electrochemical method involves attaching a more reactive metal (like $Mg$ or $Zn$) which corrodes preferentially,protecting the base metal.
$IV$. Electroplating with inert metals to protect the surface. For example,$Ag$ plating on $Cu$ or $Au$ plating on $Ag$.