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प्रश्न
Why do gold ornaments look new even after several years of use?
उत्तर
Gold is a least reactive metal. It does not react with air, water, acids, alkalis and other gases in the environment. Due to this non-reactive nature, gold metal's shine lasts for years and gold ornaments look new even after several years of use.
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संबंधित प्रश्न
The two metals which are extracted by means of electrolytic reduction of their molten salts are:
(a) magnesium and manganese
(b) iron and aluminium
(c) zinc and magnesium
(d) magnesium and aluminium
Calamine ore can be used to extract one of the following metals. This metal is:
(a) copper
(b) mercury
(c) aluminium
(d) zinc
During galvanisation, iron metal is given a thin coating of one of the following metals. This metal is:
(a) chromium
(b) tin
(c) zinc
(d) copper
Which metal can be extracted from the following ore?
Haematite
Give the chemical formula of :
Sodium aluminate
Answer the following questions based on the extraction of aluminium from alumina by Hall - Heroult’s Process :
Why is powdered coke sprinkled on top of the electrolyte?
What is meant by concentration of ores?
Complete the incomplete statement with missing word:
Metals are malleable while non-metals are ______.
X is an element in the form of a powder. X burns in oxygen and the product is soluble in water. The solution is tested with litmus. Write down only the word which will correctly complete each of the following sentences:
(a) If X is a metal, then the litmus will turn ______.
(b) If X is a non-metal, then the litmus will turn ______.
(c) If X is a reactive metal, then ______ will be evolved, when X reacts with dilute sulphuric acid.
(d) If X is a non -metal, it will form _ oxide, which will form ______ solution with water.
(e) If X is a non -metal, it will not conduct electricity unless it is carbon in the form of ______.
Bauxite reacts with sodium hydroxide in the Bayer’s process.
