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प्रश्न
Answer the following question:
What is corrosion? Do gold ornaments corrode? Justify.
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उत्तर
- The slow process of decay or distinction ions of a metal due to the effect of air, moisture, acids, alkalies, or other chemicals on it is called corrosion.
- Ordinarily, gold ornaments do not get corroded.
- Gold is one of the least reactive metals. It does not react with air, moisture, sweat, or ordinary pollutants in air or water. Hence, it does not get corroded.
APPEARS IN
संबंधित प्रश्न
What is an alloy?
Give two examples of alloys with their chemical composition.
Tinning : Tin : : Galvanizing : _________
Explain the terms Corrosion
What are alloys?
Two methods by which rusting of iron can be prevented are ______ and ______.
State two conditions for the rusting of iron.
Fill in the following blank with suitable word:
The process of depositing a thin layer of zinc on iron articles is called .............
Name any two metals which do not corrode easily.
Name an alloy of copper. State its chemical composition and any one use.
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
Brass is an alloy of:
(a) Cu and Sn
(b) Cu and Pb
(c) Pb and Sn
(d) Zn and Cu
Bronze is an alloy of ______.
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
Find the odd man out:
What are the adverse effects of corrosion?
What is ‘rusting’?
Corrosion of silver causes a black layer of _______.
Stainless steel is an alloy of _______.
When one of the metals in an alloy is mercury the alloy is called _______.
Rusting of iron : Fe2O3 : : corrosion of copper : ______
Draw a neat labelled diagram.
Electroplating
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 figure and write the answer of the question.
- Which process is shown in the figure?
- Explain the chemical reaction shown in the figure.
- Write the reactions on anode and cathode.
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.
Alloys are homogeneous mixtures of a metal with a metal or nonmetal. Which among the following alloys contain non-metal as one of its constituents?
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.
