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प्रश्न
Write a molecular formula for rust.
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उत्तर
The chemical formula of rust is Fe2O3•xH2O.
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संबंधित प्रश्न
What is an alloy?
Two methods by which rusting of iron can be prevented are ______ and ______.
Explain how painting of an iron gate prevents it from rusting.
What special name is given to their corrosion of iron?
In one method of rust prevention, the iron is not coated with anything. Which is this method?
Fill in the following blanks with suitable words:
............ and .............. are necessary for the rusting of iron.
Name any two metals which do not corrode easily.
What is the corrosion of iron known as?
What is meant by 'rusting of iron'? With the help of labelled diagrams, describe an activity to find out the conditions under which iron rusts.
Name two metals which resist corrosion due to the formation of a thin, hard and impervious layer of oxide on their surface.
Name a common metal which is highly resistant to corrosion.
A common metal which is highly resistant to corrosion is:
(a) iron
(b) copper
(c) aluminium
(d) magnesium
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
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.
A metal X which is resistant to corrosion is produced by the electrolysis of its molten oxide whereas another metal Y which is also resistant to corrosion is produced by the reduction of its oxide with carbon. Metal X can be used in powder form in thermite welding whereas metal Y is used in making cathodes of ordinary dry cells.
(a) Name the metals X and Y.
(b) Which of the two metals is more reactive : X or Y?
(c) Name one ore or metal X. Also write its chemical formula.
(d) Name one ore or metal Y. Also write its chemical formula.
(e) Name one alloy of metal X and one alloy of metal Y.
Name the metal which is a constituent of plant pigment?
Choose the correct alternative and rewrite the following:
Iron is _____________________.
Answer the following question:
What is corrosion? Do gold ornaments corrode? Justify.
Give reason.
An iron article should be given a coat of paint
Give reason.
Copper and brass utensils should be tinned.
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?
_______ is an alloy made from iron, carbon and chromium.
Which of the following method is used to prevent the accumulation of greenish layer on brass due to corrosion?
Bronze : _______ : : Stainless steel : Fe + Cr + C
Find the odd one out and give its explanation.
Write scientific reason.
Anodization method is useful for prevention of the corrosion of the aluminium.
Draw a neat labelled diagram.
Anodizing
A man painted his main gate made up of iron, to
- prevent it from rusting.
- protect it from sun.
- make it look beautiful.
- make it dust free.
Which of the above statement(s) is/are correct?
Galvanisation is a process used to prevent the rusting of which of the following?
Explain the following:
Lime water turns milky on passing carbon dioxide gas into it.
Explain the following:
Bubbles are produced when acetic acid is added to a solution of sodium hydrogencarbonate.
Give an example of a chemical reaction for the following situation:
Sound is produced
Explain the chemical reactions in rusting of iron.
