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Question
Which one of the following processes involve chemical reactions?
Options
Storing of oxygen gas under pressure in a gas cylinder
Liquefaction of air
Keeping petrol in a china dish in the open
Heating copper wire in the presence of air at high temperature.
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Solution
Heating copper wire in the presence of air at high temperature.
Explanation -
Copper will react with oxygen present in air upon strong heating to form copper (II) oxide or cupric oxide.
`2"Cu"+ underset(("Air"))("O"_2) overset("Heat")(->) 2"CuO"`
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