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Write a molecular formula for rust. - Science and Technology 1

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प्रश्न

Write a molecular formula for rust.

एक पंक्ति में उत्तर

उत्तर

The chemical formula of rust is Fe2O3•xH2O.

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अध्याय 8: Metallugy - Answer the Following

संबंधित प्रश्न

Tinning : Tin : : Galvanizing : _________


Explain why Iron sheets are coated with zinc during galvanization.


What is anodising? Give its applications.


Write a chemical equation to show the process of corrosion of iron.


What is meant by galvanisation? Why is it done?


Name the metal which is used for galvanising iron.


Explain why, iron sheets are coated with zinc.


What is corrosion?


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.


What are the constituents of stainless steel?


Explain why, when a copper object remains in damp air for a considerable time, a green coating is formed on its surface. What is this process known as?


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.


Mention two uses of the following metals and non-metals  

Iron 


What is corrosion? What are necessary conditions for corrosion?


No chemical reaction takes place when granules of a 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.

(i) Based on the given information make an assumption about A and B and write a chemical equation for the chemical reaction indicating the conditions of reaction, physical state of reactants and products and thermal status of reaction.

(ii) Mention any two types of reactions under which above chemical reaction can be classified.


Observe the following picture a write down the chemical reaction with the explanation.


Complete the process of iron rusting by filling the blanks. Suggest a way to prohibit the process.
The iron rust is formed due to........................... reaction. Different
regions on iron surface become anode and cathode.
 Reaction on anode region :

`F_e(s) → Fe^(2+) (aq) +2e^-`

 Reaction on anode region :

`O_2(g) + 4H^+(aq) +............................ → 2H_2 O (l) `

When Fe2+ ions migrate from anode region they react with ................... to form Fe3+ ions.
A reddish coloured hydrated oxide is formed from ............... ions. It is called rust.

`2Fe_(3+) (aq) + 4H_2O(l) → ................. + 6H_+(aq) `

A way to prevent rusting ..................................................................

 

 


What is "rusting"? Describe with a labelled diagram an activity to investigate the conditions under which iron rusts.


Give reason for the following:

A suspension of rust is basic in nature.


Write a short note on Alloying.


To prevent corrosion of iron and steel _______ method is used.


 _______ forms a green colour in the water.


Find the odd one out and give its explanation.


Draw a neat labelled diagram.

Electroplating


What is rust?


Give preventive methods by giving examples of corrosion?


Give the equation for the formation of rust.


The diagram shows the reaction between metal and dil. acid.

What is the reason for different behaviour of Mg in test tube B?


The table shown below gives information about four substances: A, B, C and D.

SUBSTANCE MELTING POINT (K) ELECTRICAL CONDUCTIVITY
SOLID LIQUID/ AQUEOUS
A 295 Good Good
B 1210 Poor Good
C 1890 Poor Good
D 1160 Poor Poor

Identify Ionic compounds from the above given substances.


Identify the correct statement from the following:


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?


A man painted his main gate made up of iron, to

  1. prevent it from rusting.
  2. protect it from the sun.
  3. make it look beautiful.
  4. make it dust-free.

Which of the above statement(s) is/are correct?


Give scientific reasons.

Silver amalgam is used for filling dental cavities.


Explain the chemical reactions in rusting of iron.


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