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प्रश्न
What is rust?
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उत्तर
A certain type of reddish coloured solid layer collects on iron surface. This layer is called ‘rust’.
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संबंधित प्रश्न
What is an alloy?
Give two examples of alloys with their chemical composition.
Tinning : Tin : : Galvanizing : _________
Give reasons:
Platinum, gold and silver are used to make jewellery.
Explain how painting of an iron gate prevents it from rusting.
What is anodising? Give its applications.
Name any three objects (or structures) which are gradually damaged by the corrosion of iron and steel.
The chemical reaction involved in the corrosion of iron metal is that of:
(a) oxidation as well as displacement
(b) reduction as well as combination
(c) oxidation as well as combination
(d) reduction as well as displacement
What is meant by galvanisation? Why is it done?
State two conditions for the rusting of iron.
Fill in the following blanks with suitable words:
............ and .............. are necessary for the rusting of iron.
What is corrosion?
What is the corrosion of iron known as?
Give the constituents and one use of brass.
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?
Mention two uses of the following metals and non-metals
Iron
Explain how the activity series accounts for each of the following:
tendency to corrosion
Corrosion can be an advantage in some case.Explain ?
Explain with reason:
Roasting is carried out on sulphide ores and not on carbonate ores.
Complete the process of iron rusting by filling the blanks. Suggest a way to prohibit the process.
The iron rust is formed due to........................... reaction. Different
regions on iron surface become anode and cathode.
Reaction on anode region :
`F_e(s) → Fe^(2+) (aq) +2e^-`
Reaction on anode region :
`O_2(g) + 4H^+(aq) +............................ → 2H_2 O (l) `
When Fe2+ ions migrate from anode region they react with ................... to form Fe3+ ions.
A reddish coloured hydrated oxide is formed from ............... ions. It is called rust.
`2Fe_(3+) (aq) + 4H_2O(l) → ................. + 6H_+(aq) `
A way to prevent rusting ..................................................................
Answer the following question.
List two properties of alloys.
Give reason.
An iron article should be given a coat of paint
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.
Stainless steel is an alloy of _______.
Pressure cooker : Anodizing : : Silver plated spoons : _______
Write scientific reason.
On exposure to air, silver articles turn blackish after some time.
Explain concept with example/explain with the help of a balanced equation.
Corrosion
Draw a neat labelled diagram.
Anodizing
Complete flow chart given below.
Write a molecular formula for rust.
Observe the following diagram and give answers.
- Name this method of prevention of corrosion.
- For prevention of which metal this method is used?
- What is used as anode in this method?
Observe the following diagram and write answers.
- Name the method.
- Explain the method.
- Give two examples of this method.
What is rust?
Give the equation for the formation of rust.
Amalgam is an alloy of ____________.
The table shown below gives information about four substances: A, B, C and D.
| SUBSTANCE | MELTING POINT (K) | ELECTRICAL CONDUCTIVITY | |
| SOLID | LIQUID/ AQUEOUS | ||
| A | 295 | Good | Good |
| B | 1210 | Poor | Good |
| C | 1890 | Poor | Good |
| D | 1160 | Poor | Poor |
Identify Ionic compounds from the above given substances.
