<P> When impure ( cast ) iron is in contact with water , oxygen , other strong oxidants , or acids , it rusts . If salt is present , for example in seawater or salt spray , the iron tends to rust more quickly , as a result of electrochemical reactions . Iron metal is relatively unaffected by pure water or by dry oxygen . As with other metals , like aluminium , a tightly adhering oxide coating , a passivation layer , protects the bulk iron from further oxidation . The conversion of the passivating ferrous oxide layer to rust results from the combined action of two agents , usually oxygen and water . </P>
<P> When impure ( cast ) iron is in contact with water , oxygen , other strong oxidants , or acids , it rusts . If salt is present , for example in seawater or salt spray , the iron tends to rust more quickly , as a result of electrochemical reactions . Iron metal is relatively unaffected by pure water or by dry oxygen . As with other metals , like aluminium , a tightly adhering oxide coating , a passivation layer , protects the bulk iron from further oxidation . The conversion of the passivating ferrous oxide layer to rust results from the combined action of two agents , usually oxygen and water . </P>
what type of reaction is the rusting of iron
what type of reaction is the rusting of iron
electrochemical
electrochemical