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प्रश्न
Explain concept with example/explain with the help of a balanced equation.
Corrosion
उत्तर
- The process of slow degradation of the metals due to the attack of atmospheric gases, moisture, acids, etc. on the surface of metals is called corrosion.
- Iron reacts with moist air and a deposit of reddish substance (Fe2O3.H2O) is formed on it. This substance is called rust and the corrosion of iron is known as rusting.
- Carbon dioxide in moist air reacts with the surface of copper vessel. Copper loses its lustre due to formation of a greenish layer of copper carbonate (CuCO3) on its surface. This is called patination of copper.
- Various methods such as galvanizing, tinning, alloying, etc. are used to protect metals from corrosion.
APPEARS IN
संबंधित प्रश्न
Which metals do not corrode easily?
Two methods by which rusting of iron can be prevented are ______ and ______.
Explain why Iron sheets are coated with zinc during galvanization.
Name any three objects (or structures) which are gradually damaged by the corrosion of iron and steel.
The chemical reaction involved in the corrosion of iron metal is that of:
(a) oxidation as well as displacement
(b) reduction as well as combination
(c) oxidation as well as combination
(d) reduction as well as displacement
What is meant by galvanisation? Why is it done?
Fill in the following blanks with suitable words:
Tiffin boxes are electroplated with .............. but car bumpers are electroplated with ............... to protect them from rusting.
Name any two metals which do not corrode easily.
What is the corrosion of iron known as?
Give the constituents and one use of brass.
What are the special properties of stainless steel?
A common metal which is highly resistant to corrosion is:
(a) iron
(b) copper
(c) aluminium
(d) magnesium
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
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?
Mention two uses of the following metals and non-metals
Iron
Name the metal which is a constituent of blood pigment?
Explain how the activity series accounts for each of the following:
tendency to corrosion
Compare roasting and calcination.
Explain with reason:
Roasting is carried out on sulphide ores and not on carbonate ores.
Give reason.
An iron article should be given a coat of paint
Which of the following method is used to prevent the accumulation of greenish layer on brass due to corrosion?
To prevent corrosion of iron and steel _______ method is used.
Pressure cooker : Anodizing : : Silver plated spoons : _______
Find the odd one out and give its explanation.
Find the odd one out and give its explanation.
Write scientific reason.
Anodization method is useful for prevention of the corrosion of the aluminium.
Write scientific reason.
On exposure to air, silver articles turn blackish after some time.
Draw a neat labelled diagram.
Anodizing
Complete flow chart given below.
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.
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 ____________.
Copper objects lose their shine and form green coating of ____________.
Galvanisation is a process used to prevent the rusting of which the following?
State whether the following statements are true or false:
Ships suffer a lot of damage though they are painted.
Explain the chemical reactions in rusting of iron.
| 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.
