A shipping company needs to ensure their iron cargo ships are protected from corrosion during long voyages through salty ocean water. Which strategy would be most effective for preventing corrosion for this purpose?
Attaching zinc blocks to the ship's hull as sacrificial anodes
Iron rusts when it is in contact with both water and oxygen, and dissolved salts such as sodium chloride in sea water make the water a good electrolyte, so the corrosion of an iron hull at sea is especially fast.
Zinc is more reactive than iron (it lies above iron in the reactivity series). When zinc blocks are fixed to the hull and are in electrical contact with it, the zinc loses electrons and corrodes in place of the iron, acting as the anode, while the iron hull becomes the cathode and is protected. This is called sacrificial (cathodic) protection, and it keeps working even where the hull surface is scratched; the zinc blocks are simply replaced when they wear away.
Keeping ships in dry air is not possible during long voyages, when the hull is always in sea water. Ordinary paint protects only as long as the coat is unbroken, and it chips and scratches easily in rough salty water, letting rust start underneath. Pure iron also rusts in moist, salty conditions, so using it gives no protection.
Hence, Attaching zinc blocks to the ship's hull as sacrificial anodes.
Similar Questions
In the electrolytic refining of copper, which material is used as the cathode?
A non-metal is found to be solid at room temperature, lustrous, and sublimes on heating. Which non-metal shows this unusual combination of physical properties?
A mining company discovers a new ore containing a metal from the top of the reactivity series. They want to extract this metal efficiently and economically. Which extraction method should they use?
Which of the following statements is/are true?
a. The rusting of iron can be prevented by making alloys.
b. Stainless steel is primarily an alloy of iron, chromium, and nickel.
c. An alloy is a heterogenous mixture of two or more metals.
In reactivity series metals are arranged in decreasing order of their activity. The metal which lies at the top of series is:
A mining company discovers a new metal that is low in the activity series and is found in its native state. Which extraction method should the company prioritize to obtain the pure metal efficiently?
Which of the following statements describes why metals like gold are found in a free state in nature, while metals like sodium are not?
During the oxidation of copper, its surface acquires a black coloured coating due to the formation of which of the following compounds?
Which of the following metals will not show any observable change when placed in cold water, based on their position in the reactivity series?
What is the main purpose of anodising aluminium during its surface treatment process?
Important Questions from Metals & Non-metals
Due to improper/indiscriminate disposal of hold and used computers or their parts, which of the following are released into the environment as e-waste?
1. Beryllium
2. Cadmium
3. Chromium
4. Heptachlor
5. Mercury
6. Lead
7. Plutonium
Select the correct answer using the codes given below:
Recently, there has been a concern over the short supply of a group of elements called 'rare earth metals'. Why?
1. China, which is the largest producer of these elements, has imposed some restrictions on their export.
2. Other than China, Australia, Canada and Chile, these elements are not found in any country.
3. Rare earth metals are essential for the manufacture of various kinds of electronic items and there is a growing demand for these elements.
Which of the statements given above is/are correct?
Which of the following metals CANNOT be cut with a knife?
Which of the following will be formed when dilute hydrochloric acid is added to a beaker having copper oxide ?
Which of the following statement is incorrect regarding metals?
