Practice Questions
🔢 Practice Numericals
Solution:
- General formula of alkanes: CₙH₂ₙ₊₂
- For n = 8: C₈H₂(₈)₊₂ = C₈H₁₈
Solution:
- CH₃COOH + NaOH → CH₃COONa + H₂O
- Moles of NaOH = 40/40 = 1 mole
- 1 mole NaOH needs 1 mole CH₃COOH
- Mass of CH₃COOH = 1 × 60 = 60g
🎯 Application-Based Questions
Answer: Methanol is oxidized in the body to formaldehyde and formic acid, which are highly toxic and can cause blindness and death. Ethanol is oxidized to acetaldehyde and acetic acid, which are less toxic and can be processed by the body.
Answer: Hard water contains Ca²⁺ and Mg²⁺ ions. These react with soap to form insoluble precipitates (scum): 2C₁₇H₃₅COONa + Ca²⁺ → (C₁₇H₃₅COO)₂Ca + 2Na⁺. This reduces soap’s effectiveness and causes scum formation.
Answer: Carbon has 4 valence electrons. To achieve stable octet, it needs 4 more electrons. Losing 4 electrons requires very high energy (becoming C⁴⁺), and gaining 4 electrons is difficult due to nuclear attraction. Therefore, carbon shares electrons through covalent bonding, which is energetically favorable.
Answer: Commercial ethanol is prepared by fermentation of sugar-containing materials: C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ (using yeast enzymes) Sugar from sugarcane, corn, or other plant materials is fermented under controlled conditions to produce ethanol.
Answer: Esters have pleasant, fruity odors that resemble natural fruit smells. They are stable, safe for consumption, and can be synthesized easily. Different esters produce different fruit-like odors (banana, apple, pineapple, etc.), making them ideal for artificial flavoring in food industry.