Moderate

In a reaction, 3 moles of electrons are gained by 1 mole of HNO3. Assuming no change in the oxidation number of hydrogen and oxygen, the possible product obtained due to reduction will be:

Correct answer: C. 0.5 mole of NO

  • A. 1 mole of NO2
  • B. 0.5 mole of N2O
  • C. 0.5 mole of NO
  • D. 0.5 mole of N2O3

Explanation

The key to solving this question lies in determining the change in oxidation state of nitrogen in HNO3 during reduction. In HNO3, nitrogen is at an oxidation state of +5. Reduction involves a decrease in this oxidation state. The reduction of 1 mole of HNO3 gaining 3 moles of electrons results in a product where nitrogen is at an oxidation state of +2, which corresponds to NO. Hence, the correct answer is 0.5 mole of NO.Other options do not match the stoichiometry or the oxidation state change: NO2 has an N oxidation state of +4, N2O has an average N oxidation state of +1, and N2O3 has an average N oxidation state of +3.

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Electrochemistry describes electron transfer through oxidation and reduction, identifies oxidizing and reducing agents, and applies oxidation numbers to balance redox equations. It also covers electrode potential and the standard hydrogen electrode, which provides the reference for comparing the reduction tendencies of other electrodes.

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