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प्रश्न
Name two metals which resist corrosion due to the formation of a thin, hard and impervious layer of oxide on their surface.
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उत्तर
Aluminium and zinc are two metals that resist corrosion due to the formation of a thin, hard and impervious layer of oxide on their surface. Aluminium and zinc form tough layers of aluminium oxide and zinc oxide by reacting with air.
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संबंधित प्रश्न
Give two examples of alloys with their chemical composition.
What is the corrosion of iron known as?
Give the constituents and one use of brass.
What are the constituents of stainless steel?
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?
Brass is an alloy of:
(a) Cu and Sn
(b) Cu and Pb
(c) Pb and Sn
(d) Zn and Cu
Name the metal which is a constituent of plant pigment?
Corrosion can be an advantage in some case.Explain ?
Compare roasting and calcination.
Give reason.
A wooden article should be polished.
Give reason.
Copper and brass utensils should be tinned.
State whether the statement given below is true or false. If false write the correct statement.
Either oxygen or moisture is essential for rusting.
Stainless steel is an alloy of _______.
Write scientific reason.
On exposure to air, silver articles turn blackish after some time.
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 ____________.
Amalgam is an alloy of ____________.
Explain the following:
Bubbles are produced when acetic acid is added to a solution of sodium hydrogencarbonate.
| A process of forming a thick oxide of aluminium when aluminium is exposed to air. This coat makes it resistant to corrosion. Resistance can be improved by making a layer of oxide thinker. In this technique, the aluminium article is the anode, and the electrolyte is sulphuric acid. The anode reaction results in the formation of a black-coloured film of aluminium oxide on the anode. By putting appropriate dyes in the electrolytic solution, both coloured surface with the decorative finish is achieved. Kitchen articles like anodised such as pressure cookers, pans and frames of sliding windows are applications of this technique. |
- Name the anode and electrolyte used in this technique.
- How can we make aluminium articles made resistant to corrosion?
- Name the technique used to coat the aluminium articles.
