CBSE Class 10 Science 2025 — Independently Prepared Solutions
Rigorous step-by-step solutions for CBSE Class 10 Science 2025 Board Examination (Code 31/1/1), covering chemical reactions, electricity circuit calculations, ray optics lens formula, and genetic inheritance.
Solutions and conceptual explanations are independently prepared by QuizCluster. QuizCluster is an independent educational platform and is not affiliated with, endorsed by, or sponsored by the Central Board of Secondary Education (CBSE). Official question papers are accessed via direct external links to official CBSE repositories and are never hosted or mirrored on QuizCluster.
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Q1 of 39Practice chapter-wise adaptive MCQs to strengthen weak concepts from this board paper.
View all years for this subjectRedox Reactions & Oxidation States
Step 1: Analyze oxidation state changes
In MnO₂, Mn is in +4 oxidation state, which decreases to +2 in MnCl₂ (Gain of electrons / Loss of oxygen = Reduction). In HCl, chlorine is in -1 oxidation state, which increases to 0 in Cl₂ (Loss of electrons / Loss of hydrogen = Oxidation).
Step 2: Identify oxidizing and reducing agents
The substance reduced (MnO₂) acts as the oxidizing agent because it causes HCl to oxidize. The substance oxidized (HCl) acts as the reducing agent.
- Oxidation: Addition of oxygen / Loss of hydrogen / Loss of electrons
- Reduction: Addition of hydrogen / Loss of oxygen / Gain of electrons
An oxidizing agent gets reduced in the process; a reducing agent gets oxidized.
Writing products (MnCl₂ or Cl₂) as the oxidizing/reducing agents. Agents are always reactant species.
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