Question

The given diagram shoe a boat made from iron. Some magnesium block are attached to the iron below the water line to prevent rusting. Why?

• A. Magnesium reacts is preference to the iron
• B. The magnesium form an alloy with the iron
• C. Magnesium react to form a protective coating of magnesium hydroxide on the iron
• D. The magnesium stops oxygen in the water from getting to the iron

Answer 1

The correct option is A Magnesium reacts is preference to the iron

Some magnesium block is attached to the iron below the water line to prevent rusting because Magnesium prevents iron from rusting. Magnesium is more reactive than iron.
So Magnesium loses electrons in preference to iron. Magnesium reacts with the oxygen in the air to form Magnesium Oxide, and the iron remains protected because it has magnesium attached to it. Magnesium is oxidised as it dissolves. Iron ions are reduced to iron atoms. The iron ions take the electrons given out by magnesium and form iron metal. Rusty iron is returned to iron metal.