Redox Reactions NEET Previous Year Questions (PYQs)
Practice NEET previous year questions from Redox Reactions. These MCQs cover oxidation number, oxidising and reducing agents, disproportionation reactions and balancing of redox equations with answers and clear explanations.
👉 Read theory:
Redox Reactions Chapter Notes
Q1. The species undergoing disproportionation is:
(NEET 2018)
- (A) Br2
- (B) BrO3−
- (C) Br−
- (D) HOBr
Show Answer
(D)
Show Explanation
In HOBr, bromine undergoes both oxidation and reduction, hence disproportionation.
Q2. Correct decreasing order of oxidation states of nitrogen in NO3−, NO, NO2− is:
(NEET 2018)
- (A) NO3− > NO > NO2−
- (B) NO > NO3− > NO2−
- (C) NO2− > NO > NO3−
- (D) NO > NO2− > NO3−
Show Answer
(A)
Show Explanation
Oxidation states: NO3− (+5) > NO (+2) > NO2− (+3).
Q3. For the redox reaction, the correct coefficients of reactants are:
(NEET 2018)
- (A) 16, 5, 2
- (B) 2, 5, 16
- (C) 2, 16, 5
- (D) 5, 16, 2
Show Answer
(B)
Show Explanation
Balancing oxidation and reduction half reactions gives coefficients 2 : 5 : 16.
Q4. Hot concentrated sulphuric acid does NOT act as an oxidising agent in:
(NEET 2016)
- (A) Cu + H2SO4
- (B) C + H2SO4
- (C) S + H2SO4
- (D) NaCl + H2SO4
Show Answer
(D)
Show Explanation
In reaction with NaCl, oxidation state of elements remains unchanged.
Q5. The pair of compounds that can exist together is:
(NEET 2014)
- (A) FeCl3, SnCl2
- (B) HgCl2, SnCl2
- (C) FeCl2, SnCl2
- (D) FeCl3, KI
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(C)
Show Explanation
Both FeCl2 and SnCl2 are reducing agents and do not react with each other.
Q6. Role of H2O2 in two reactions is respectively oxidising and reducing. Correct option is:
(NEET 2014)
- (A) Oxidising in both
- (B) Reducing in both
- (C) Oxidising in one, reducing in another
- (D) Neither
Show Answer
(C)
Show Explanation
Hydrogen peroxide can act as both oxidising and reducing agent depending on medium.
Q7. In acidic medium, Cr2O72− changes to CrO5. Oxidation state of Cr in CrO5 is:
(NEET 2014)
- (A) +6
- (B) +5
- (C) +3
- (D) −10
Show Answer
(B)
Show Explanation
CrO5 has peroxo bonds; oxidation state of Cr is +5.
Q8. When Cl2 reacts with hot concentrated NaOH, oxidation number of Cl changes from:
(NEET 2012)
- (A) 0 to −1 and +1
- (B) 0 to −1 and +5
- (C) 0 to +1 and +5
- (D) 0 to −1 and +7
Show Answer
(B)
Show Explanation
This is a disproportionation reaction forming Cl− and ClO3−.
Q9. In a mixture of KClO3, oxalic acid and H2SO4, which element undergoes maximum change in oxidation number?
(NEET 2012)
- (A) K
- (B) C
- (C) Cl
- (D) S
Show Answer
(C)
Show Explanation
Chlorine changes from +5 to −1, which is maximum change.
Q10. Number of moles of KMnO4 required to oxidise one mole of oxalate ion in acidic medium is:
(NEET 2008)
- (A) 0.2
- (B) 0.4
- (C) 0.6
- (D) 0.8
Show Answer
(A)
Show Explanation
2 moles of KMnO4 oxidise 5 moles of oxalate ions.
Q11. Which describes behaviour of bromine in HOBr formation?
(NEET 2004)
- (A) Oxidised only
- (B) Reduced only
- (C) Both oxidised and reduced
- (D) Neither
Show Answer
(C)
Show Explanation
Bromine undergoes both oxidation and reduction.
Q12. Oxidation state of sulphur in SO32− and SO42− follows the order:
(NEET 2003)
- (A) +4 < +6
- (B) +6 < +4
- (C) 0 < +6
- (D) +2 < +4
Show Answer
(A)
Q13. Oxidation state of Fe in Fe3O4 is:
(NEET 1999)
- (A) +2
- (B) +3
- (C) +8/3
- (D) +4
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(C)
Q14. Which of the following is a redox reaction?
(NEET 1997)
- (A) Evaporation of water
- (B) Neutralisation
- (C) Reaction of Cl2 with NaOH
- (D) Dissolution of sugar
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(C)
Q15. Which oxide cannot act as a reducing agent?
(NEET 1995)
- (A) CO
- (B) SO2
- (C) CO2
- (D) NO
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(C)
Q16. In the reaction, Ni acts as:
(NEET 1994)
- (A) Oxidising agent
- (B) Reducing agent
- (C) Catalyst
- (D) Neither
Show Answer
(B)
Q17. Oxidation state of iodine in ICl3 is:
(NEET 1994)
- (A) −1
- (B) +1
- (C) +3
- (D) +5
Show Answer
(C)
👉 More Redox Reactions NEET PYQs will be added gradually.