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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.
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संबंधित प्रश्न
Which of the following methods is suitable for preventing an iron frying pan from rusting?
Explain why Iron sheets are coated with zinc during galvanization.
Choose the correct answer from the options given below:
Heating an ore in a limited supply of air or in the absence of air at a temperature just below its melting point is known as
A. Smelting
B. Ore-dressing
C. Calcination
D. Bessemerisation
What is anodising? Give its applications.
Write a chemical equation to show the process of corrosion of iron.
What type of chemical reaction is involved in the corrosion of iron?
Name the metal which is used for galvanising iron.
Explain why, iron sheets are coated with zinc.
Fill in the following blank with suitable word:
The corrosion of copper produces a .............. coating of basic copper carbonate on its surface
Fill in the following blanks with suitable words:
............ and .............. are necessary for the rusting of iron.
Why is an iron grill painted frequently?
Explain why, through aluminium is more reactive than iron, yet there is less corrosion of aluminium when both are exposed to air.
Name any two metals which do not corrode easily.
Name two metals which resist corrosion due to the formation of a thin, hard and impervious layer of oxide on their surface.
What are the constituents of stainless steel?
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
Find the odd man out:
Write three methods of preventing rusting of iron.
Write a short note on Alloying.
Observe the following picture and answer the following questions:
- What is rust?
- 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?
Pressure cooker : Anodizing : : Silver plated spoons : _______
Write the name.
An alloy of copper and tin-
Write scientific reason.
Anodization method is useful for prevention of the corrosion of the aluminium.
Write scientific reason.
Coins are made from metals and alloys.
Draw a neat labelled diagram.
Electroplating
What is rust?
Observe the following diagram and give answers.
- Name this method of prevention of corrosion.
- For prevention of which metal this method is used?
- What is used as anode in 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.
State two conditions necessary for rusting of iron.
Copper objects lose their shine and form green coating of ____________.
Which among the following alloys contain mercury as one of its constituents?
Alloys are homogeneous mixtures of a metal with a metal or nonmetal. Which among the following alloys contain non-metal as one of its constituents?
Galvanisation is a process used to prevent the rusting of which the following?
Explain the following:
Lime water turns milky on passing carbon dioxide gas into it.
In ______ process a layer of molten tin is deposited on metals.
