Chemical Reactions Exemplar — Class 10 Science NCERT Solutions (Free)
Free step-by-step NCERT solutions for Class 10 Science chapter "Chemical Reactions Exemplar" — 5 important questions with detailed answers for CBSE board exam preparation.
TL;DR: Free step-by-step NCERT solutions for Class 10 Science chapter "Chemical Reactions Exemplar" — 5 important questions with detailed answers for CBSE bo…
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Key Questions Covered:
- What is a chemical reaction? Classify the reaction: 2H2 + O2 → 2H2O.
- Distinguish between displacement and double displacement reactions.
- Balance the chemical equation: Fe + Cl2 → FeCl3.
- What is decomposition reaction? Give one example.
- Write balanced equation for combustion of methane and classify it.
Solutions Summary:
| Question | Status |
|---|---|
| What is a chemical reaction? Classify the reaction: 2H2 +… | ✓ Solved |
| Distinguish between displacement and double displacement … | ✓ Solved |
| Balance the chemical equation: Fe + Cl2 → FeCl3. | ✓ Solved |
| What is decomposition reaction? Give one example. | ✓ Solved |
| Write balanced equation for combustion of methane and cla… | ✓ Solved |
Showing 5 of 5 questions
Q1: What is a chemical reaction? Classify the reaction: 2H2 + O2 → 2H2O.
Chemical reaction is transformation of substances resulting in formation of new substances with different properties. The reaction 2H2 + O2 → 2H2O is a combination reaction (two or more reactants combine to form one product). It is also an exothermic reaction (heat is released).
Q2: Distinguish between displacement and double displacement reactions.
Displacement reaction: A + BC → AC + B (one element displaces another). Example: Fe + CuSO4 → FeSO4 + Cu. Double displacement: AB + CD → AD + CB (two compounds exchange ions). Example: AgNO3 + NaCl → AgCl (ppt) + NaNO3.
Q3: Balance the chemical equation: Fe + Cl2 → FeCl3.
Iron has 3 electrons in valence, chlorine takes 1. So Fe forms FeCl3. Left: 1 Fe, 2 Cl. Right: 1 Fe, 3 Cl. Balance: 2Fe + 3Cl2 → 2FeCl3.
Q4: What is decomposition reaction? Give one example.
Decomposition reaction is breaking down of one compound into two or more simpler substances. Example: 2H2O → 2H2 + O2 (when electricity is passed, electrolytic decomposition). Another: CaCO3 → CaO + CO2 (thermal decomposition).
Q5: Write balanced equation for combustion of methane and classify it.
CH4 + 2O2 → CO2 + 2H2O. Combustion is a reaction where a substance burns in oxygen, releasing heat and light. This is exothermic (heat releasing) and oxidation-reduction (redox) reaction.
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