Relevant Titles
-
CBSE Class 11 Chemistry Redox and Oxidation Numbers MCQs with Answers
-
NCERT Class 11 Redox Reaction and Oxidation Number Practice Test
-
Class 11 Chemistry Online Quiz – Redox and Oxidation Number Concepts
-
Important Redox and Oxidation Number Questions for Class 11 CBSE Exam
-
Free CBSE Class 11 Redox and Oxidation Number MCQ Test (NCERT-Based)
📘 Introduction
Understanding Redox Reactions and Oxidation Numbers is a crucial part of CBSE Class 11 Chemistry, especially for board exams and competitive entrance tests like JEE and NEET. This online MCQ Practice Test on “Redox and Oxidation Numbers” has been carefully designed according to the NCERT Class 11 Chemistry Chapter 8 – Redox Reactions. It helps students strengthen their conceptual clarity of oxidation number rules, redox balancing, and identification of oxidizing and reducing agents.
Each multiple-choice question comes with detailed answers and explanations to ensure conceptual understanding. By practicing these MCQs, students can assess their preparation level, enhance problem-solving speed, and gain confidence in tackling similar questions in board exams. These CBSE Class 11 Chemistry MCQs strictly follow the NCERT syllabus and cover all important topics such as oxidation number calculation, redox balancing, and identification of oxidation-reduction processes.
Get started now and boost your score with this free Redox and Oxidation Numbers MCQ Test designed for CBSE Class 11 Chemistry learners.
Sample MCQs (with Answers & Explanations):
Q1. The oxidation number of Cr in K₂Cr₂O₇ is:
A) +3 B) +6 C) +4 D) +5
Answer: B) +6
Explanation: In K₂Cr₂O₇, 2(K⁺) = +2 and 7(O²⁻) = –14. Let total Cr charge = x, so 2x + 2 – 14 = 0 → 2x = 12 → x = +6.
Q2. The oxidation number of oxygen in hydrogen peroxide (H₂O₂) is:
A) –2 B) –1 C) 0 D) +1
Answer: B) –1
Explanation: Hydrogen is +1 each → total +2. Sum = 0, so 2x + 2 = 0 → x = –1.
Q3. Which element is oxidized in the reaction Zn + 2HCl → ZnCl₂ + H₂?
A) Zn B) H C) Cl D) None
Answer: A) Zn
Explanation: Zn changes from 0 to +2 oxidation state, losing electrons—thus it is oxidized.
Q4. In the reaction 2H₂O₂ → 2H₂O + O₂, oxygen is:
A) Only reduced B) Only oxidized C) Both oxidized and reduced D) Unchanged
Answer: C) Both oxidized and reduced
Explanation: One O atom changes from –1 to 0 (oxidized), and another from –1 to –2 (reduced)—a disproportionation reaction.
Q5. In MnO₄⁻ → Mn²⁺, the decrease in oxidation number of Mn is:
A) 3 B) 5 C) 7 D) 2
Answer: B) 5
Explanation: Mn goes from +7 in MnO₄⁻ to +2 in Mn²⁺. Hence, it gains 5 electrons—reduction by 5 units.