Exam Notes
Carbon and its Compounds Class 10 Science Recap — Grandmaster Guide
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Last Updated: 2026-04-23
- Allotropy of carbon: diamond, graphite, fullerenes
- Carbon catenation: ability of carbon to form long chains and rings
- Tetravalency of carbon: carbon has 4 valence electrons
- sp³, sp², sp hybridization of carbon
- Homologous series: CH₄, C₂H₆, C₃H₈, ...
- General formula for alkanes: CₙH₂ₙ₊₂
- General formula for alkenes: CₙH₂ₙ
- General formula for alkynes: CₙH₂ₙ₋₂
- Combustion reaction of alkanes: CₙH₂ₙ₊₂ + (3n+1)/2O₂ → nCO₂ + (n+1)H₂O
- Combustion reaction of alkenes: CₙH₂ₙ + (3n/2)O₂ → nCO₂ + nH₂O
- Combustion reaction of alkynes: CₙH₂ₙ₋₂ + (3n/2-1)O₂ → nCO₂ + (n-1)H₂O
🪤 The 5 Mistakes That Cost Marks
- Not understanding the difference between saturated and unsaturated hydrocarbons
- Confusing the general formulas for alkanes, alkenes, and alkynes
- Not being able to write the structural formulas for isomers of alkanes
- Forgetting the combustion reactions of alkanes, alkenes, and alkynes
- Not being able to identify the functional groups ∈ organic compounds
✏️ 3 Solved PYQs
- Question 1: What is the general formula for alkenes? Step 1: Recall the definition of alkenes Step 2: Recall the general formula for alkenes: CₙH₂ₙ Answer: CₙH₂ₙ
- Question 2: Write the structural formula for but-2-ene Step 1: Recall the definition of alkenes Step 2: Recall the general formula for alkenes: CₙH₂ₙ Step 3: Draw the structural formula for but-2-ene: CH₃-CH=CH-CH₃ Answer: CH₃-CH=CH-CH₃
- Question 3: What is the combustion reaction of methane? Step 1: Recall the definition of combustion reaction Step 2: Recall the combustion reaction of methane: CH₄ + 2O₂ → CO₂ + 2H₂O Answer: CH₄ + 2O₂ → CO₂ + 2H₂O
🧠 The One Thing Most Students Get Wrong
- Most students get confused between the general formulas for alkanes, alkenes, and alkynes
- They need to remember that the general formula for alkanes is CₙH₂ₙ₊₂, for alkenes is CₙH₂ₙ, and for alkynes is CₙH₂ₙ₋₂
👁️ Ayush's Note
- To solve problems related to carbon and its compounds, first recall the general formulas for alkanes, alkenes, and alkynes
- Then, recall the combustion reactions of alkanes, alkenes, and alkynes
- Practice writing the structural formulas for isomers of alkanes
- Make a list of functional groups ∈ organic compounds and practice identifying them
🔁 Last 5 Minutes Box
- Recall the allotropy of carbon: diamond, graphite, fullerenes
- Recall the tetravalency of carbon: carbon has 4 valence electrons
- Recall the hybridization of carbon: sp³, sp², sp
- Recall the general formulas for alkanes, alkenes, and alkynes
- Recall the combustion reactions of alkanes, alkenes, and alkynes
📝 Practice MCQs
1. What is the general formula for alkanes?
A) CₙH₂ₙ
B) CₙH₂ₙ₊₂
C) CₙH₂ₙ₋₂
D) CₙH₂ₙ₊₁
Answer: B) CₙH₂ₙ₊₂
2. What is the combustion reaction of ethene?
A) C₂H₄ + 3O₂ → 2CO₂ + 2H₂O
B) C₂H₄ + 2O₂ → 2CO₂ + 2H₂O
C) C₂H₄ + O₂ → 2CO₂ + 2H₂O
D) C₂H₄ + 4O₂ → 2CO₂ + 2H₂O
Answer: B) C₂H₄ + 3O₂ → 2CO₂ + 2H₂O
3. What is the structural formula for propyne?
A) CH₃-CH=CH
B) CH₃-CH₂-CH₃
C) CH₃-C≡CH
D) CH₃-CH=CH₂
Answer: C) CH₃-C≡CH
4. What is the functional group ∈ methane?
A) -OH
B) -COOH
C) -CH₃
D) None
Answer: D) None
5. What is the hybridization of carbon ∈ diamond?
A) sp³
B) sp²
C) sp
D) None
Answer: A) sp³
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This post was curated by Jules, Exam Compass Bot, and edited for accuracy by Ayush.
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