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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
Explain the term corrosion.
What is anodising? Give its applications.
What type of chemical reaction is involved in the corrosion of iron?
State two conditions for the rusting of iron.
The corrosion of copper produces a ______ coating of basic copper carbonate on its surface.
Name two metals which resist corrosion due to the formation of a thin, hard and impervious layer of oxide on their surface.
Name an alloy of copper. State its chemical composition and any one use.
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?
Brass is an alloy of ______.
Mention two uses of the following metals and non-metals
Iron
Name the metal which is a constituent of blood pigment?
Name the metal which is a constituent of plant pigment?
Explain how the activity series accounts for each of the following:
tendency to corrosion
Corrosion can be an advantage in some case.Explain ?
What are the adverse effects of corrosion?
Write three methods of preventing rusting of iron.
Answer the following question.
List two properties of alloys.
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.
Give reason for the following:
A suspension of rust is basic in nature.
State whether the statement given below is true or false. If false write the correct statement.
Either oxygen or moisture is essential 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.
_______ is an alloy made from iron, carbon and chromium.
Which of the following method is used to prevent the accumulation of greenish layer on brass due to corrosion?
Write the name.
An alloy of copper and tin-
Write scientific reason.
Anodization method is useful for prevention of the corrosion of the aluminium.
Draw a neat labelled diagram.
Electroplating
Complete flow chart given below.
What is rust?
State two conditions necessary for rusting of iron.
Galvanisation is a method of protecting iron from rusting by coating it with a thin layer of ____________.
Amalgam is an alloy of ____________.
Copper objects lose their shine and form green coating of ____________.
Galvanisation is a process used to prevent the rusting of which of the following?
State whether the following statement is true or false:
Ships suffer a lot of damage though they are painted.
Give scientific reasons.
Silver amalgam is used for filling dental cavities.
In ______ process a layer of molten tin is deposited on metals.
