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प्रश्न
Fill in the following blanks with suitable words:
Tiffin boxes are electroplated with .............. but car bumpers are electroplated with ............... to protect them from rusting.
उत्तर
Tiffin boxes are electroplated with tin but car bumpers are electroplated with chromium to protect them from rusting.
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संबंधित प्रश्न
Write two methods of preventing the rusting of iron.
Which metals do not corrode easily?
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
Write a chemical equation to show the process of corrosion of iron.
What is meant by galvanisation? Why is it done?
State two conditions for the rusting of iron.
A common metal which is highly resistant to corrosion is:
(a) iron
(b) copper
(c) aluminium
(d) magnesium
Brass is an alloy of:
(a) Cu and Sn
(b) Cu and Pb
(c) Pb and Sn
(d) Zn and Cu
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.
Explain with reason:
Roasting is carried out on sulphide ores and not on carbonate ores.
Find the odd man out:
What is done to prevent corrosion of metals?
Write the name.
Method used to prevent corrosion of copper.
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.
What is rust?
Galvanisation is a method of protecting iron from rusting by coating it with a thin layer of ____________.
Give an example of a chemical reaction for each of the following situations:
Sound is produced
Describe two changes that are harmful. Explain why you consider them harmful. How can you prevent them?
