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प्रश्न
What is corrosion?
उत्तर १
Corrosion is the damage caused to the metal by the chemical reaction of air, water and acids with the surface of the metal. Generally reactive metals corrode easily and non-reactive metals have good resistance to corrosion.
उत्तर २
Metals get attacked by substances around it such as moisture, acids, etc. Metal is said to ‘corrode’ due to this attack and the process is called corrosion.
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संबंधित प्रश्न
Give two examples of alloys with their chemical composition.
Write two methods of preventing the rusting of iron.
Why do we apply paint on iron articles?
Explain the terms Corrosion
Which of the following methods is suitable for preventing an iron frying pan from rusting?
Give reasons:
Platinum, gold and silver are used to make jewellery.
Explain how painting of an iron gate prevents it from rusting.
What is anodising? Give its applications.
Name any three objects (or structures) which are gradually damaged by the corrosion of iron and steel.
What is meant by galvanisation? Why is it done?
Explain why, iron sheets are coated with zinc.
Fill in the following blank with suitable word:
The process of depositing a thin layer of zinc on iron articles is called .............
Fill in the following blanks with suitable words:
Tiffin boxes are electroplated with .............. but car bumpers are electroplated with ............... to protect them from rusting.
Fill in the following blanks with suitable words:
............ and .............. are necessary for the rusting of iron.
Explain why, through aluminium is more reactive than iron, yet there is less corrosion of aluminium when both are exposed to air.
What is the corrosion of iron known as?
Name two metals which resist corrosion due to the formation of a thin, hard and impervious layer of oxide on their surface.
Name an alloy of copper. State its chemical composition and any one use.
In stainless steel alloy, iron metal is mixed with:
(a) Cu and Cr
(b) Cr and Ni
(c) Cr and Sn
(d) Cu and Ni
No chemical reaction takes place when granules of a rusty-brown solid A are mixed with the powder of another solid B. However, when the mixture is heated, a reaction takes place between its components. One of the products C is a metal and settles down in the molten state while the other product D floats over it. It was observed that the reaction is highly exothermic.
(a) What could the solids A and B be?
(b) What are the products C and D most likely to be?
(c) Write the chemical equation for the reaction between A and B leading to the formation of C and D. Mention the physical states of all the reactants and products in this equation and indicate the heat change which takes place.
(d) What is the special name of such a reaction? State one use of such a reaction.
(e) Name any two types of chemical reactions under which the above reaction can be classified.
Four metals P, Q, R and S are all obtained by the reduction of their oxides with carbon. Metal P is used to form a thin layer over the sheets of metal S to prevent its corrosion. Metal Q is used for electroplating tiffin boxes made of metal S whereas metal R is used in making car batteries. Metals Q and R form an alloy called solder. What are metals P, Q, R and S? How have you arrived at this conclusion?
Name the metal which is a constituent of blood pigment?
State under what conditions corrosion is faster ?
Corrosion can be an advantage in some case.Explain ?
Answer the following question.
a) What is meant by corrosion?
b) Write names of any two methods of prevention of corrosion.
c) In which method, metal like copper, aluminium are coated with a thin layer of their oxides by means of electrolysis.
d) Explain this method with diagram.
What is done to prevent corrosion of metals?
Write three methods of preventing rusting of iron.
What is "rusting"? Describe with a labelled diagram an activity to investigate the conditions under which iron rusts.
Give reason.
A wooden article should be polished.
Give reason.
Copper and brass utensils should be tinned.
Explain the term – rusting and give a word equation for the formation of rust. If polished iron nails are kept in three separate test tubes, state the contents in each test tube required, to prove the conditions for rusting.
Give reason for the following:
A suspension of rust is basic in nature.
Write a short note on Alloying.
When one of the metals in an alloy is mercury the alloy is called _______.
Find the odd one out and give its explanation.
Write the name.
An alloy of copper and tin-
Complete flow chart given below.
Write a molecular formula for rust.
Observe the following diagram and write answers.
- Name the method.
- Explain the method.
- Give two examples of this method.
Observe the following figure and write the answer of the question.
- Which process is shown in the figure?
- Explain the chemical reaction shown in the figure.
- Write the reactions on anode and cathode.
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 ______
What is rust?
Which among the following alloys contain mercury as one of its constituents?
The diagram shows the reaction between metal and dil. acid.
What is the reason for different behaviour of Mg in test tube B?
Marble’s popularity began in ancient Rome and Greece, where white and off-white marble were used to construct a variety of structures, from hand-held sculptures to massive pillars and buildings.
The substance not likely to contain CaCO3 is:
Identify the correct statement from the following:
Galvanisation is a process used to prevent the rusting of which the following?
Give an example of a chemical reaction for each of the following situations:
Sound is produced
| 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.
In ______ process a layer of molten tin is deposited on metals.
