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प्रश्न
Give reasons.
Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
Explain why aluminium is a highly reactive metal. Still, it is used to make utensils for cooking.
उत्तर
- Aluminium is a highly reactive metal. It reacts easily with oxygen in the air and forms a layer of aluminium oxide on its surface.
- This aluminium oxide layer is very tough and does not allow air to enter the metal for further reaction, preventing further corrosion of aluminium.
- Therefore, aluminium articles become unreactive towards air and water and do not corrode easily due to the presence of a strong aluminium oxide layer over them.
- This oxide layer on aluminium is made further stronger by making it thicker through a process called anodising. This prevents corrosion to the maximum. Hence, aluminium becomes highly resistant to corrosion and is used to make cooking utensils.
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संबंधित प्रश्न
Name one metal which is extracted by reduction with carbon.
What is the difference between a mineral and an ore?
Give the name of one ore of iron. Which iron compound is present in this ore? Write its chemical formula.
An ore of manganese metal is:
(a) bauxite
(b) haematite
(c) cuprite
(d) pyrolusite
The major ore of aluminium is known as:
(a) cinnabar
(b) calamine
(c) bauxite
(d) pyrolusite
Which of the following metals are extracted by the electrolysis of their molten chlorides?
(a) Na and Hg
(b) Hg and Mg
(c) Na and Mg
(d) Cu and Fe
Aluminum is used in thermite welding:
write reaction for process?
Name the following:
The substance added to get rid of gangue in the extraction of metal.
Name the following:
Name two metals always find in combined state.
Compare the process of calcination and roasting.
Explain the following:
Galvanization protects iron from rusting.
Complete the incomplete statement with missing word:
Metals form positive ions while non- metals ______.
X is an element in the form of a powder. X burns in oxygen and the product is soluble in water. The solution is tested with litmus. Write down only the word which will correctly complete each of the following sentences:
(a) If X is a metal, then the litmus will turn ______.
(b) If X is a non-metal, then the litmus will turn ______.
(c) If X is a reactive metal, then ______ will be evolved, when X reacts with dilute sulphuric acid.
(d) If X is a non -metal, it will form _ oxide, which will form ______ solution with water.
(e) If X is a non -metal, it will not conduct electricity unless it is carbon in the form of ______.
choose the most appropriate term to match the given description.
Heating of the ore in the absence of air to high temperature
Observe the given figure of reactivity series of metals and answer the following questions:
Reactivity series of metals
- Name two metals which react with water.
- Name two moderately reactive metals.
- Name the most highly reactive metal and the most less reactive metal.
Write the name.
The molecular formula of main ore of aluminium –
Explain the concept of Roasting.
Explain the concept of Calcination.
Complete flow chart given below.
