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प्रश्न
Give reasons:
Platinum, gold and silver are used to make jewellery.
Give a reason for the following:
Silver, gold and platinum are used to make jewellery.
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उत्तर
- Gold, silver, and platinum are the least reactive metals. They do not react with air, water, acids, alkalis, or other gases in the environment, so their shine lasts for years.
- Due to their bright lustre and resistance to corrosion, gold, silver, and platinum are used to make jewellery.
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संबंधित प्रश्न
Write two methods of preventing the rusting of iron.
Choose the correct answer from the options given below:
Heating an ore in a limited supply of air or in the absence of air at a temperature just below its melting point is known as
A. Smelting
B. Ore-dressing
C. Calcination
D. Bessemerisation
What type of chemical reaction is involved in the corrosion of iron?
Explain why, iron sheets are coated with zinc.
State two conditions for the rusting of iron.
Give the constituents and one use of brass.
In stainless steel alloy, iron metal is mixed with:
(a) Cu and Cr
(b) Cr and Ni
(c) Cr and Sn
(d) Cu and Ni
Brass is an alloy of:
(a) Cu and Sn
(b) Cu and Pb
(c) Pb and Sn
(d) Zn and Cu
What is corrosion? What are necessary conditions for corrosion?
Answer the following question:
What is corrosion? Do gold ornaments corrode? Justify.
Give reason.
An iron article should be given a coat of paint
Give reason for the following:
A suspension of rust is basic in nature.
Observe the following picture and answer the following questions:
- What is rust?
- Write the chemical formula of rust.
- Write the reaction of oxidation of iron at the anode.
- Write the reaction of oxidation of iron at the cathode.
- What is corrosion?
_______ is an alloy made from iron, carbon and chromium.
Write the name.
An alloy of copper and tin-
Write scientific reason.
On exposure to air, silver articles turn blackish after some time.
Draw a neat labelled diagram.
Electroplating
Observe the following diagram and write answers.
- Name the method.
- Explain the method.
- Give two examples of this method.
State whether the following statement is true or false:
Ships suffer a lot of damage though they are painted.
