Advertisements
Advertisements
प्रश्न
Why is an iron grill painted frequently?
Advertisements
उत्तर
To prevent rusting of iron substances, they are painted frequently. Iron is a reactive metal and it starts corroding in the presence of air (oxygen) and water (or moisture). Iron reacts with oxygen present in the moist air and forms a brown flaky iron oxide (or rust) layer on its surface. This is called rusting. This rusting causes huge damage to iron substances by making them weak. Therefore, an iron grill is painted frequently to prevent corrosion.
APPEARS IN
संबंधित प्रश्न
Give two examples of alloys with their chemical composition.
Tinning : Tin : : Galvanizing : _________
Answer the following question.
What are alloys?
Fill in the following blanks with suitable words:
............ and .............. are necessary for the rusting of iron.
Explain why, through aluminium is more reactive than iron, yet there is less corrosion of aluminium when both are exposed to air.
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 five methods of preventing rusting of iron.
Explain why, the galvanised iron article is protected against rusting even if the zinc layer is broken.
Brass is an alloy of:
(a) Cu and Sn
(b) Cu and Pb
(c) Pb and Sn
(d) Zn and Cu
What is corrosion? What are necessary conditions for corrosion?
Answer the following question.
a) What is meant by corrosion?
b) Write names of any two methods of prevention of corrosion.
c) In which method, metal like copper, aluminium are coated with a thin layer of their oxides by means of electrolysis.
d) Explain this method with diagram.
Choose the correct alternative and rewrite the following:
Iron is _____________________.
Write three methods of preventing rusting of iron.
Give reason for the following:
A suspension of rust is basic in nature.
Bronze : _______ : : Stainless steel : Fe + Cr + C
Write the name.
An alloy of copper and tin-
The process of coating the surface of the metal with a thin layer of zinc is called ______
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?
Give scientific reasons.
Silver amalgam is used for filling dental cavities.
Describe two changes that are harmful. Explain why you consider them harmful. How can you prevent them?
