Question

जेव्हा काळ्या कॉपर ऑक्साईडवरून -------------- वायू प्रवाहित केला जातो तेव्हा तांबूस रंगाचे तांबे मिळते. / When -------- gas is passed over black copper oxide a raddish coloured layer of copper is formed. *



1. नायट्रोजन / Nitrogen
2. सल्फर डाय ऑक्साईड / Sulphur dioxide
3. हायड्रोजन / Hydrogen
4. कार्बन डाय ऑक्साईड / Carbon dioxide​

Answer 1

Explanation:

3hydrogen gas is passed over black copper oxide

Answer 2

When 3. Hydrogen gas is passed over black copper oxide a reddish coloured layer of copper is form

• Copper oxide is black in colour which reacts with hydrogen gas. The products formed are copper metal and water.
• The reaction is single displacement reaction which displace copper ions from the copper oxide compound.
• In this reaction, Hydrogen is the reductant or reducing agent. It reduces copper ions to the metallic copper.
• On the other hand, copper oxide is oxidising agent or oxidant. It oxidises hydrogen making it lose electron.
• The chemical reaction stating the interchange of mentioned ions is as follows -

CuO + $H _{2}$ --> ${Cu}$ + $H _{2}O$

• In the mentioned balanced chemical reaction, CuO is copper oxide, $H _{2}$ refers to hydrogen gas, Cu refers to copper metal and $H _{2}O$ is the chemical formula of water.
• Hence, hydrogen when passed over copper oxide, results in production of reddish colour copper metal.

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