Class 10 Chemistry Worksheet on Chapter 4 Carbon and Its compounds ... - Free Printable

Let’s solve each question step by step with clear explanations.

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Q-6: Catenation refers to an atom's ability to form bonds with other atoms of the same element. Carbon and silicon both exhibit it. Compare the ability of the two elements to catenate. Give your reasoning.

✔ Answer:

Carbon has a much greater ability to catenate than silicon.

🔹 Reasoning:

Catenation is the ability of an element to form long chains or rings by bonding with itself. Both carbon and silicon are in Group 14 and have 4 valence electrons, so they can form four covalent bonds. However:

- Carbon-carbon (C–C) bonds are stronger than silicon-silicon (Si–Si) bonds.
- Bond dissociation energy of C–C bond ≈ 348 kJ/mol
- Bond dissociation energy of Si–Si bond ≈ 222 kJ/mol

- The smaller atomic size of carbon allows for better orbital overlap, leading to stronger sigma bonds.

- Silicon atoms are larger, so their orbitals overlap less effectively, resulting in weaker bonds.

- Also, silicon has vacant 3d orbitals that can interact with oxygen, making it more likely to form silicates (with O) rather than long Si–Si chains.

- Carbon forms stable chains up to thousands of atoms (e.g., polymers, DNA, proteins), while silicon chains rarely exceed 7–8 atoms and are unstable under normal conditions.

➡️ Therefore, carbon exhibits superior catenation ability compared to silicon.

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Q-7: Write the names of the following compounds?

We’ll name them using IUPAC rules.

(a)
Structure:
```
H H H
| | |
H — C — C — C — OH
| | |
H H H
```

This is a 3-carbon chain with –OH on terminal carbon → Propan-1-ol (or 1-Propanol)

✔ Name: Propan-1-ol

(b)
Structure:
```
H H O
| | ||
H — C — C — C — OH
| | |
H H H
```

3-carbon chain with carboxylic acid group (–COOH) → Propanoic acid

✔ Name: Propanoic acid

(c)
Structure:
```
H H O H H
| | || | |
H — C — C — C — C — C — H
| | | |
H H H H
```

5-carbon chain with ketone group at carbon #3 → Pentanone, specifically Pentan-3-one

✔ Name: Pentan-3-one

(d)
Structure:
```
H H H H
| | | |
H — C — C — C = C — H
| |
H H
```

4-carbon chain with double bond starting at carbon #1 → Butene, specifically But-1-ene

✔ Name: But-1-ene

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Q-8: What is the function of the metals or reagents indicated on arrows in the given chemical reactions?

(a)
Reaction:
(CH₃)₂C=C(CH₃)₂ + H₂ → (CH₃)₂CH–CH(CH₃)₂
Reagent: Ni

✔ Function: Nickel (Ni) acts as a heterogeneous catalyst for the hydrogenation of alkenes. It provides a surface for H₂ to adsorb and react with the alkene, reducing the double bond to single bond.

(b)
Reaction:
CH₃COOH + CH₃CH₂OH → CH₃COOC₂H₅ + H₂O
Reagent: Conc. H₂SO₄

✔ Function: Concentrated sulfuric acid acts as a catalyst and dehydrating agent in esterification. It protonates the carbonyl oxygen, making the carboxylic acid more electrophilic, and removes water to shift equilibrium toward ester formation.

(c)
Reaction:
CH₃CH₂OH → CH₃COOH
Reagent: Alk. KMnO₄, Heat

✔ Function: Alkaline potassium permanganate (KMnO₄) is a strong oxidizing agent. It oxidizes primary alcohols (like ethanol) to carboxylic acids (ethanoic acid). Heat ensures complete oxidation.

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Q-9: Fill in the blanks

a) The lowest molecular mass alkane which shows chain isomerism is ________.

🔹 Explanation:

Chain isomerism occurs when compounds have the same molecular formula but different arrangements of the carbon skeleton.

- Methane (CH₄), Ethane (C₂H₆), Propane (C₃H₈) → no chain isomers possible (only one way to arrange).

- Butane (C₄H₁₀) → has two isomers:
- n-Butane: straight chain
- Isobutane (2-methylpropane): branched chain

✔ So, the lowest molecular mass alkane showing chain isomerism is Butane (C₄H₁₀).

➡️ Answer: Butane

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✔ Final Answers Summary:

Q-6: Carbon has greater catenation ability than silicon due to stronger C–C bonds, smaller atomic size, and better orbital overlap.

Q-7:
(a) Propan-1-ol
(b) Propanoic acid
(c) Pentan-3-one
(d) But-1-ene

Q-8:
(a) Ni → Catalyst for hydrogenation
(b) Conc. H₂SO₄ → Catalyst & dehydrating agent for esterification
(c) Alk. KMnO₄ → Oxidizing agent for alcohol → carboxylic acid

Q-9:
a) Butane

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