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प्रश्न
Explain why, the surface of some metals acquires a dull appearance when exposed to air for a long time.
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उत्तर
Most of the metals are reactive towards air. They react with oxygen present in the air to form metal oxides. The metal oxide formation appears on the surface of the metals as a thin layer. This thin layer formation of metal oxide on the metallic surface causes the dull appearance of the metals. Thus, the surface of some metals acquires a dull appearance when exposed to air for a long time.
संबंधित प्रश्न
Iron is
(a) More reactive than zinc
(b) More reactive than aluminium
(c) Less reactive than copper
(d) Less reactive than aluminium
You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.
Why are metals called electropositive elements?
Name the metal which has been placed at the top of the reactivity series.
Name the metal which has been placed just below copper in the reactivity series.
What will happen if a strip of zinc is immersed in a solution of copper sulphate?
Magnesium liberates ______ gas on reacting with hot boiling water.
Explain why, metals usually do not liberate hydrogen gas with dilute nitric acid.
Name two metals which can, however, liberate hydrogen gas from very dilute nitric acid.
What happens when magnesium reacts with very dilute nitric acid? Write an equation for the reaction involved.
A copper plate was dipped in AgNO3 solution. After certain time, silver from the solution was deposited on the copper plate. State the reason why it happened. Give the chemical equation of the reaction involved.
Which non-metal has been placed in the reactivity series of metals?
One of the following is not a neutral oxide. This is:
An element is soft and can be cut with a knife. It is very reactive and cannot be kept open in the air. It reacts vigorously with water. The element is most likely to be ______.
An element X forms two oxides XO and XO2. The oxide XO has no action on litmus solution but oxide XO2 turns litmus solution red.
- What is the nature of oxide XO?
- What is the nature of oxide ХО2?
- Would you call element X a metal or a non-metal? Give reason for your choice.
- Can you give an example of element like X?
State and explain the reaction of the following metal with a solution of copper sulphate:
Gold
\[\ce{CuSO4_{(aq)} + Fe_{(s)} -> FeSO4_{(aq)} + Cu_{(s)}}\]
\[\ce{FeSO4_{(aq)} + Zn_{(s)} -> ZnSO4_{(aq)} + Fe_{(s)}}\]
On the basis of the above reactions, indicate which is most reactive and which is least reactive metal out of zinc, copper and iron.
What are noble gases?
What is the characteristic of the electronic configuration of noble gases?
