Redox Reactions NEET PYQs (1994–2026)

Solved Redox Reactions PYQs

3 recent questions with answers. The full set of 31 is free to practise.

1. NEET 2026EasyOxidation States
   Q1

   The correct decreasing order of oxidation state of the underlined
   
   atom in each molecule is:

   • AP₄O₁₀ > SO₃ > H₂O
   • BN₂O₅ > Al₂O₃ > H_zS
   • CSO₃ > P₄O₁₀ > H₂O
   • DP₄O₆ > Cl₂O₇ > AlH₃

   Show answer & solution

   Correct answer: (B)

   B
2. NEET 2026HardRedox Reactions
   Q2

   Given below are two statements:
   
   Statement I: Heating NaCl with concentrated H₂SO₄ and MnO₂ results in oxidation of Mn.
   
   Statement II: Heating NaI with concentrated H₂SO₄ and MnO₂ results in reduction of Mn.
   
   In light of the above statements, choose the most appropriate answer from the options given below:

   • ABoth Statement I and Statement II are correct
   • BBoth Statement I and Statement II are incorrect
   • CStatement I is correct but Statement II is incorrect
   • DStatement I is incorrect but Statement II is correct

   Show answer & solution

   Correct answer: (D)

   With NaCl: MnO₂ + 4HCl → MnCl₂ + Cl₂ + 2H₂O. Mn goes from +4 to +2 (reduction). So Statement I is incorrect.
   
   With NaI: MnO₂ + 4HI → MnI₂ + I₂ + 2H₂O. Mn goes from +4 to +2 (reduction). So Statement II is correct.
   
   So Statement I incorrect, Statement II correct.
3. NEET 2023MediumBalancing Redox Reactions
   Q3

   On balancing the given redox reaction,
   
   $${aCr}_2{O}_7{}^{2-}+{bSO}_3{}^{2-}(aq)+{cH}^{+}(aq)\to 2{aCr}^{3+}(aq)+{bSO}_4{}^{2-}(aq)+\frac{c}{2}{H}_{2}O(l)$$
   
   the coefficients $a,b$ and $c$ are found to be, respectively-
   [NEET 2023]

   • A3,8,1
   • B1,8,3
   • C$8,1,3$
   • D$1,3,8$

   Show answer & solution

   Correct answer: (D)

   Using Ion electron method:
   Reduction Half reaction : ${Cr}_2{O}_7{}^{2-}+6e^{-}\to 2{Cr}^{3+}$
   Oxidation Half reaction: ${SO}_3{}^{2-}\to {SO}_4{}^{2-}+2{}^{-}\times 3$
   Overall reaction : ${Cr}_2{O}_7{}^{2-}+3{SO}_3{}^{2-}\to 2{Cr}^{3+}+3{SO}_4{}^{2-}$
   
   To balance ' O ' atoms, adding $H_{2}O$ on LHS
   
   $${Cr}_2{O}_7^{2-}+3{SO}_3^{2-}\to 2{Cr}^{3+}+3{SO}_4^{2-}+4H_{2}O$$
   
   To balance ' H ' atoms, adding $H^{+}$on RHS
   
   $$\begin{array}{cc}& {Cr}_2{O}_7^{2-}+3{SO}_3^{2-}+8H^{+}\to 2{Cr}^{3+}+3{SO}_4^{2-}+4H_{2}O\\ & \therefore a=1\\ & b=3\\ & c=8\end{array}$$

Topic-wise question count

Where NEET has asked from Redox Reactions, most frequent first.

• Oxidation States13
• Redox Reactions7
• Disproportionation Reactions4
• Balancing Redox Reactions3
• Oxidizing and Reducing Agents3
• Redox Couples1

Year-wise Redox Reactions questions in NEET

Number of questions from this chapter in each year's paper(s).