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Q83 (NDA-I/2025) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Basic chemical principles Answer Verified

Which one of the following statements regarding oxidation and reduction reactions is NOT correct ?

Result
Your answer: —  Â·  Correct: A
Explanation

In chemical reactions, oxidation and reduction are defined by the transfer of oxygen and hydrogen. Oxidation is characterized by the gain of oxygen or the loss of hydrogen [3]. Conversely, reduction is defined as the loss of oxygen or the gain of hydrogen [3]. Therefore, if a substance loses hydrogen during a reaction, it is being oxidized, not reduced [3]. This makes statement 1 incorrect. Statements 2, 3, and 4 are accurate descriptions of redox processes: losing oxygen is reduction [2], gaining hydrogen is reduction [3], and gaining oxygen is oxidation [3]. Modern definitions also include electron transfer, where oxidation is the loss of electrons and reduction is the gain of electrons, often remembered by the mnemonic 'OIL RIG'.

Sources

  1. [1] Science , class X (NCERT 2025 ed.) > Chapter 1: Chemical Reactions and Equations > CuO +H Cu+H O 2 2 → Heat (1.29) > p. 12
  2. [3] Science , class X (NCERT 2025 ed.) > Chapter 1: Chemical Reactions and Equations > CuO +H Cu+H O 2 2 → Heat (1.29) > p. 13
  3. [2] Science , class X (NCERT 2025 ed.) > Chapter 1: Chemical Reactions and Equations > What you have learnt > p. 14
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SIMILAR QUESTIONS

NDA-I · 2012 · Q19 Relevance score: 7.05

Which of the following statements regarding oxidation and reduction are correct? 1. In oxidation, loss of electron takes place whereas in reduction, gain of electron takes place. 2. In oxidation, gain of electron takes place whereas in reduction, loss of electron takes place. 3. Oxidizing agent decreases the oxidation number but reducing agent increases the oxidation number. 4. Oxidizing agent increases the oxidation number but reducing agent reduces the oxidation number. Select the correct answer using the code given below ; Code:

CDS-II · 2016 · Q27 Relevance score: 5.44

Which one of the following statements is correct?

NDA-I · 2019 · Q32 Relevance score: 5.15

Which one of the following statements is NOT correct for the given reaction?

CDS-I · 2016 · Q43 Relevance score: 5.02

Which one of the following statements is not correct?

NDA-I · 2012 · Q40 Relevance score: 4.07

The following equation is an example of a redox reaction, in which Cl2 is the oxidizing agent and FeBr3 is the reducing agent : 2FeBr3 (aq) + 3Cl2 (g) = 2FeCl 3 (aq) + 3Br2 (l) Which one among the following statements is incorrect for this redox reaction?