All Exams Test series for 1 year @ ₹349 only
Question

Consider the following statements regarding oxidation numbers:
I. The oxidation number of oxygen in peroxides and superoxides is assigned as -1 and -1/2 respectively.
II. In all its compounds, fluorine has an oxidation number of -1.
III. In a reduction half-reaction, the oxidation number of the reductant decreases.
Which of the statements given above are correct?

This question was previously asked in
NDA 2 2026 GAT Question Paper (13-Sep-2026)
The correct answer is

I and II only

Statement I is correct: in peroxides (e.g., H2O2) oxygen is assigned an oxidation number of -1, and in superoxides (e.g., KO2) it is assigned -1/2. Statement II is correct: fluorine, being the most electronegative element, always has an oxidation number of -1 in all its compounds. Statement III is incorrect: in a reduction half-reaction it is the oxidant (the species being reduced) whose oxidation number decreases, not the reductant's; the reductant itself is oxidised, so its oxidation number increases. Hence, only statements I and II are correct.

Was this answer helpful?

Similar Questions

  1. Which one of the following methods can be used to separate anthracene from a mixture of salt and anthracene ?

  2. Which one of the following is called dry ice?

  3. Which one of the following statements about the law of conservation of mass is correct?

  4. Which among the following are essential constituents of Portland cement?

  5. Number of molecules of water of crystallization in copper sulphate, sodium carbonate and Gypsum are

  6. The compound C6H12 O4 contains________.

  7. Which one of the following is a non-metallic mineral?

  8. When pure water boils vigorously, the bubbles that rise to the surface are composed primarily of

  9. How much CO 2is produced on heating of 1 kg of carbon?

  10. 20 g of common salt is dissolved in 180 g of water. What is the mass percentage of the salt in the solution?


Important Questions from Basic Concepts of Chemistry

  1. Which of the following pair is correct?

    I. Isotopes – different mass numbers

    II. Isobars – different atomic numbers

  2. Which of the following is a zone of a flame?

    I. Dark

    II. Luminous

    III. Non-Luminous

  3. The volume of CO 2liberated at STP when 10 gm of 90% pure limestone strongly heated is

  4. Water can dissolve more substances than any other liquid because

  5. An alloy is:

Need Expert Advice?
Test Series
NDA img
Defence
NDA 2026 Mock Test Series (Latest Pattern)
526 Tests 1 Tests Free
1164 Attempts
4.7(159)
English, Hindi

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App