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प्रश्न
Explain why, the galvanised iron article is protected against rusting even if the zinc layer is broken.
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उत्तर
The galvanised iron-zinc oxide layer coating on iron objects prevents zinc and iron under it from corrosion. This happens because zinc is more reactive than iron. If the zinc layer is broken, zinc, being more reactive, gets oxidised before iron and prevents its corrosion.
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संबंधित प्रश्न
Two methods by which rusting of iron can be prevented are ______ and ______.
Name any three objects (or structures) which are gradually damaged by the corrosion of iron and steel.
State two conditions for the rusting of iron.
Explain why, when a copper object remains in damp air for a considerable time, a green coating is formed on its surface. What is this process known as?
If copper is kept exposed to damp air for a considerable time, it gets a green coating on its surface. This is due to the formation of:
(a) hydrated copper sulphate
(b) copper oxide
(c) basic copper carbonate
(d) copper nitrate
Brass is an alloy of:
(a) Cu and Sn
(b) Cu and Pb
(c) Pb and Sn
(d) Zn and Cu
Observe the following picture a write down the chemical reaction with the explanation.
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Choose the correct alternative and rewrite the following:
Iron is _____________________.
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State whether the statement given below is true or false. If false write the correct statement.
Graphite is a lustrous non-metal which conducts electricity.
Observe the following picture and answer the following questions:
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- Write the chemical formula of rust.
- Write the reaction of oxidation of iron at the anode.
- Write the reaction of oxidation of iron at the cathode.
- What is corrosion?
Rusting of iron : Fe2O3 : : corrosion of copper : ______
What is rust?
Give preventive methods by giving examples of corrosion?
The process of coating the surface of the metal with a thin layer of zinc is called ______
Galvanisation is a method of protecting iron from rusting by coating it with a thin layer of ____________.
Explain the following:
Lime water turns milky on passing carbon dioxide gas into it.
Describe two changes that are harmful. Explain why you consider them harmful. How can you prevent them?
