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प्रश्न
Explain the terms Corrosion
Explain the term "corrosion" with an example.
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उत्तर १
Corrosion is defined as a process where materials, usually metals, deteriorate as a result of a chemical reaction with air, moisture, chemicals, etc. For example, in the presence of moisture, iron reacts with oxygen to form hydrated iron oxide.
\[\ce{4Fe + 3O2 + H2O → 2Fe2O3.nH2O}\]
उत्तर २
Corrosion is a process where a refined metal is oxidised by atmospheric oxygen to form a more stable compound, such as oxides. The metal gradually degrades during the corrosion process. Iron rusting is a good example of corrosion, where the iron is converted to iron oxide. Millions of dollars are spent annually to prevent rusting on bridges and other monuments.
उत्तर ३
Corrosion is the process by which metal corrodes when it comes into contact with its surroundings, such as moisture, air, and acids. For example, a powdered (brown) coating on iron objects such as iron railings.
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संबंधित प्रश्न
Give two examples of alloys with their chemical composition.
Explain why, iron sheets are coated with zinc.
Fill in the following blanks with suitable words:
............ and .............. are necessary for the rusting of iron.
What are the special properties of stainless steel?
Name a common metal which is highly resistant to corrosion.
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
Bronze is an alloy of ______.
What is corrosion? What are necessary conditions for corrosion?
Complete the process of iron rusting by filling the blanks. Suggest a way to prohibit the process.
The iron rust is formed due to........................... reaction. Different
regions on iron surface become anode and cathode.
Reaction on anode region :
`F_e(s) → Fe^(2+) (aq) +2e^-`
Reaction on anode region :
`O_2(g) + 4H^+(aq) +............................ → 2H_2 O (l) `
When Fe2+ ions migrate from anode region they react with ................... to form Fe3+ ions.
A reddish coloured hydrated oxide is formed from ............... ions. It is called rust.
`2Fe_(3+) (aq) + 4H_2O(l) → ................. + 6H_+(aq) `
A way to prevent rusting ..................................................................
What is ‘rusting’?
Give reason.
Copper and brass utensils should be tinned.
Stainless steel is an alloy of _______.
Rusting of iron : Fe2O3 : : corrosion of copper : ______
Bronze : _______ : : Stainless steel : Fe + Cr + C
Write scientific reason.
Coins are made from metals and alloys.
Which among the following alloys contain mercury as one of its constituents?
Generally, when metals are treated with mineral acids, hydrogen gas is liberated but when metals (except Mn and Mg), treated with HNO3, hydrogen is not liberated, why?
Iron pillar near the Qutub Minar in Delhi is famous for the following facts. Which of these facts is responsible for its long stability?
| 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.
