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Redox Reactions — NEET & JEE Chemistry MCQs

30 questions written by hand against the NCERT chapter. Every wrong option is explained, not just the right one.

30questions
10/14/6easy / medium / hard
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Sample questions from this chapter

How is oxidation defined in terms of electron transfer?
  1. Loss of electrons by a species ✓
  2. Gain of electrons by a species
  3. Acceptance of a proton by a species
  4. Sharing of an electron pair between species
Answer: A. Oxidation is electron loss and reduction is electron gain; the two occur simultaneously because released electrons must be accepted. The oxidised species is therefore the electron donor.
Why not B: Gain of electrons is reduction, remembered by the complementary half-reaction.
Why not C: Proton acceptance defines Brønsted basicity rather than oxidation.
Why not D: Electron-pair sharing describes covalent bond formation and need not change oxidation states.
What is the oxidation number of sulphur in H2SO4?
  1. +4
  2. -6
  3. +6 ✓
  4. +8
Answer: C. 2(+1) + S + 4(−2) = 0, so S = +6. The +4 trap commonly comes from counting only three of the four oxygen atoms.
Why not A: +4 belongs to sulphur in SO2 or sulphite and results here from omitting one oxygen contribution.
Why not B: This assigns the balancing magnitude the wrong sign.
Why not D: This cancels hydrogen but treats each oxygen as contributing only −1.
Which coefficient set balances MnO4- + Fe2+ + H+ → Mn2+ + Fe3+ + H2O in acidic medium, in that order?
  1. 1, 5, 8, 1, 5, 4 ✓
  2. 1, 1, 8, 1, 1, 4
  3. 2, 5, 16, 2, 5, 8
  4. 1, 5, 4, 1, 5, 2
Answer: A. The reduction half uses 5e− and 8H+: MnO4− + 8H+ + 5e− → Mn2+ + 4H2O. Adding five Fe2+ → Fe3+ + e− gives coefficients 1,5,8,1,5,4.
Why not B: This balances atoms other than charge but fails to supply five Fe2+ for permanganate's five-electron reduction.
Why not C: Doubling only the permanganate, acid and water coefficients leaves iron and charge unbalanced.
Why not D: Four H+ and two waters leave oxygen and hydrogen short by two each.

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Other NEET Chemistry chapters

Some Basic Concepts of ChemistryStructure of AtomClassification of Elements and Periodicity in PropertiesChemical Bonding and Molecular StructureThermodynamicsEquilibrium

All 19 chapters →

Questions

How many NEET and JEE questions are there on Redox Reactions?

This chapter test has 30 questions — 10 easy, 14 medium and 6 hard — all written against the NCERT Class 11 chapter.

Is this NEET and JEE Chemistry chapter test free?

Yes. Every chapter test is free with no login, and you get your all-India rank on every one. Nothing on the site is on sale right now.

Do the questions explain the wrong options?

Yes — every distractor carries its own explanation naming the specific misconception that makes a student pick it. That is the part most question banks skip, and it is the part that changes your next attempt.