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प्रश्न
Corrosion of silver causes a black layer of _______.
विकल्प
Silver nitrate
silver oxide
silver sulphide
silver carbonate
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उत्तर
Corrosion of silver causes a black layer of silver sulphide.
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संबंधित प्रश्न
Give two examples of alloys with their chemical composition.
Answer the following question.
What are alloys?
What special name is given to their corrosion of iron?
State two conditions for the rusting of iron.
Fill in the following blank with suitable word:
The corrosion of iron is called ................
Name any two metals which do not corrode easily.
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.
What are the constituents of stainless steel?
What are the special properties of stainless steel?
If copper is kept exposed to damp air for a considerable time, it gets a green coating on its surface. This is due to the formation of:
(a) hydrated copper sulphate
(b) copper oxide
(c) basic copper carbonate
(d) copper nitrate
Mention two uses of the following metals and non-metals
Iron
What is corrosion? What are necessary conditions for corrosion?
Explain with reason:
Roasting is carried out on sulphide ores and not on carbonate ores.
Write scientific reasons.
Lemon or tamarind is used for cleaning copper vessels turned greenish.
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.
a) What is meant by corrosion?
b) Write names of any two methods of prevention of corrosion.
c) In which method, metal like copper, aluminium are coated with a thin layer of their oxides by means of electrolysis.
d) Explain this method with diagram.
What is done to prevent corrosion of metals?
Choose the correct alternative and rewrite the following:
Iron is _____________________.
Write three methods of preventing rusting of iron.
Answer the following question.
List two properties of alloys.
Give reason.
A wooden article should be polished.
Give reason.
Copper and brass utensils should be tinned.
_______ is an alloy made from iron, carbon and chromium.
To prevent corrosion of iron and steel _______ method is used.
When one of the metals in an alloy is mercury the alloy is called _______.
Rusting of iron : Fe2O3 : : corrosion of copper : ______
Bronze : _______ : : Stainless steel : Fe + Cr + C
Find the odd one out and give its explanation.
Find the odd one out and give its explanation.
Write scientific reason.
Anodization method is useful for prevention of the corrosion of the aluminium.
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?
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.
Marble’s popularity began in ancient Rome and Greece, where white and off-white marble were used to construct a variety of structures, from hand-held sculptures to massive pillars and buildings.
The substance not likely to contain CaCO3 is:
A man painted his main gate made up of iron, to
- prevent it from rusting.
- protect it from sun.
- make it look beautiful.
- make it dust free.
Which of the above statement(s) is/are correct?
State whether the following statement is true or false:
Ships suffer a lot of damage though they are painted.
Explain the following:
Lime water turns milky on passing carbon dioxide gas into it.
