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प्रश्न
Write scientific reason.
On exposure to air, silver articles turn blackish after some time.
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उत्तर
- Silver articles turn blackish after some time of exposure to air. This is because silver undergoes corrosion when exposed to air containing hydrogen sulphide.
- Silver reacts with hydrogen sulphide in air to form a layer of silver sulphide \[\ce{(Ag2S)}\], which gives silver articles a blackish appearance.
संबंधित प्रश्न
Why do we apply paint on iron articles?
Which metals do not corrode easily?
What are alloys?
Which of the following methods is suitable for preventing an iron frying pan from rusting?
Explain how painting of an iron gate prevents it from rusting.
Name any three objects (or structures) which are gradually damaged by the corrosion of iron and steel.
State two conditions for the rusting of iron.
The corrosion of iron is called ______.
The process of depositing a thin layer of zinc on iron articles is called ______.
The corrosion of copper produces a ______ coating of basic copper carbonate on its surface.
Name five methods of preventing rusting of iron.
In stainless steel alloy, iron metal is mixed with ______.
Bronze is an alloy of ______.
Explain how the activity series accounts for each of the following:
tendency to corrosion
What is corrosion? What are necessary conditions for corrosion?
Corrosion can be an advantage in some case.Explain ?
Give reason.
An iron article should be given a coat of paint
Give reason.
A wooden article should be polished.
Give reason.
Copper and brass utensils should be tinned.
Explain the term – rusting and give a word equation for the formation of rust. If polished iron nails are kept in three separate test tubes, state the contents in each test tube required, to prove the conditions for rusting.
State whether the statement given below is true or false. If false write the correct statement.
Graphite is a lustrous non-metal which conducts electricity.
Which of the following method is used to prevent the accumulation of greenish layer on brass due to corrosion?
Stainless steel is an alloy of _______.
Write scientific reason.
Coins are made from metals and alloys.
Draw a neat labelled diagram.
Electrolysis
Complete flow chart given below.
What is rust?
State two conditions necessary for rusting of iron.
The diagram shows the reaction between metal and dil. acid.
What is the reason for different behaviour of Mg in test tube B?
Generally, when metals are treated with mineral acids, hydrogen gas is liberated but when metals (except Mn and Mg), treated with HNO3, hydrogen is not liberated, why?
Iron pillar near the Qutub Minar in Delhi is famous for the following facts. Which of these facts is responsible for its long stability?
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.
In ______ process a layer of molten tin is deposited on metals.
Describe two changes that are harmful. Explain why you consider them harmful. How can you prevent them?
