Top Redox Reactions Questions for NEET

Redox reactions are one of the most fundamental and high-weightage topics in NEET Chemistry. Questions from oxidation number, balancing redox equations, and equivalent concept are asked almost every year. If you master the Top 5 Redox Reactions Questions, you can confidently solve both conceptual and numerical problems in the exam.

In this article, we will go through the Top 5 Redox Reactions Questions that are frequently repeated in NEET PYQs. Along with step-by-step solutions, you will also learn important tricks to solve questions quickly and accurately.

Question 1: Oxidation Number Calculation

Find the oxidation number of chromium in $K_2Cr_2O_7$K2​Cr2​O7​.

Detailed Explanation

Let the oxidation number of Cr = $x$x

We know:

• K = +1
• O = -2

Applying the rule:$$2(+1) + 2x + 7(-2) = 0$$2(+1)+2x+7(−2)=0 $$2 + 2x – 14 = 0$$2+2x−14=0 $$2x – 12 = 0 \Rightarrow x = +6$$2x−12=0⇒x=+6

Final Answer:

Oxidation number of Cr = +6

This is one of the most basic yet frequently asked problems in the Top 5 Redox Reactions Questions.

Question 2: Identification of Oxidation and Reduction

Identify which species is oxidized and which is reduced:$$Zn + Cu^{2+} \rightarrow Zn^{2+} + Cu$$Zn+Cu2+→Zn2++Cu

Detailed Explanation

• Zn → Zn²⁺ (loss of electrons) → Oxidation
• Cu²⁺ → Cu (gain of electrons) → Reduction

Final Answer:

Zn is oxidized, and Cu²⁺ is reduced.

This is a conceptual question commonly included in the Top 5 Redox Reactions Questions.

Question 3: Balancing Redox Reaction (Ion-Electron Method)

Balance the reaction in acidic medium:$$MnO_4^- + Fe^{2+} \rightarrow Mn^{2+} + Fe^{3+}$$MnO4−​+Fe2+→Mn2++Fe3+

Detailed Explanation

Step 1: Write half-reactions

Reduction:$$MnO_4^- \rightarrow Mn^{2+}$$MnO4−​→Mn2+

Oxidation:$$Fe^{2+} \rightarrow Fe^{3+}$$Fe2+→Fe3+

Step 2: Balance oxygen and hydrogen$$MnO_4^- + 8H^+ \rightarrow Mn^{2+} + 4H_2O$$MnO4−​+8H+→Mn2++4H2​O

Step 3: Balance electrons$$MnO_4^- + 8H^+ + 5e^- \rightarrow Mn^{2+} + 4H_2O$$MnO4−​+8H++5e−→Mn2++4H2​O $$Fe^{2+} \rightarrow Fe^{3+} + e^-$$Fe2+→Fe3++e−

Step 4: Equalize electrons and combine$$MnO_4^- + 8H^+ + 5Fe^{2+} \rightarrow Mn^{2+} + 4H_2O + 5Fe^{3+}$$MnO4−​+8H++5Fe2+→Mn2++4H2​O+5Fe3+

Final Answer:

$$MnO_4^- + 8H^+ + 5Fe^{2+} \rightarrow Mn^{2+} + 4H_2O + 5Fe^{3+}$$MnO4−​+8H++5Fe2+→Mn2++4H2​O+5Fe3+

Balancing reactions is one of the most important parts of the Top 5 Redox Reactions Questions.

Question 4: Equivalent Weight Concept

Find the equivalent weight of $KMnO_4$KMnO4​ in acidic medium.

Detailed Explanation

Equivalent weight = Molecular weight / n-factor

In acidic medium:

• Mn changes from +7 to +2
• Change in oxidation number = 5

Thus, n-factor = 5

Equivalent weight:$$\frac{158}{5} = 31.6$$5158​=31.6

Final Answer:

Equivalent weight = 31.6

This concept is frequently tested in the Top 5 Redox Reactions Questions.

Question 5: Disproportionation Reaction

Identify whether the following is a disproportionation reaction:$$2H_2O_2 \rightarrow 2H_2O + O_2$$2H2​O2​→2H2​O+O2​

Detailed Explanation

In $H_2O_2$H2​O2​, oxygen has oxidation number -1.

After reaction:

• In $H_2O$H2​O: O = -2 (reduction)
• In $O_2$O2​: O = 0 (oxidation)

Same element undergoes both oxidation and reduction.

Final Answer:

Yes, it is a disproportionation reaction.

This is a classic concept included in the Top 5 Redox Reactions Questions.

Why These Top 5 Redox Reactions Questions Are Important

The Top 5 Redox Reactions Questions represent the most important and repeated patterns in NEET. Questions are usually:

• Concept-based with simple calculations
• Focused on oxidation number and balancing
• Derived from standard NCERT examples

If you practice these Top 5 Redox Reactions Questions, you can solve most redox problems in NEET with ease.

Tricks to Solve Redox Questions Faster

To master the Top 5 Redox Reactions Questions, follow these tricks:

Always remember basic oxidation number rules. Practice half-reaction method regularly. In equivalent weight questions, quickly identify n-factor. Look for disproportionation patterns where one element undergoes both oxidation and reduction.

These tricks will help you solve the Top 5 Redox Reactions Questions quickly during the exam.

Common Mistakes Students Make

While practicing the Top 5 Redox Reactions Questions, students often make errors such as:

Incorrect oxidation number calculation. Skipping steps while balancing equations. Confusing oxidation with reduction. Miscalculating n-factor.

Avoiding these mistakes will significantly improve your accuracy.

FAQs on Top 5 Redox Reactions Questions

Is redox reactions important for NEET?

Yes, it is a fundamental topic and contributes at least 1–2 questions.

Are balancing questions difficult?

No, with practice of the Top 5 Redox Reactions Questions, they become easy.

What is the most important concept in redox?

Oxidation number and balancing reactions are the most important.

How to improve speed in redox?

Practice regularly and use shortcut methods.

Conclusion

The Top 5 Redox Reactions Questions covered in this article include the most repeated and important concepts for NEET. From oxidation number to balancing equations, these topics form the foundation of redox chemistry.

By consistently practicing these Top 5 Redox Reactions Questions, you can improve both speed and accuracy, ensuring better performance in NEET.