Organic Basics — Set 1
Chemistry · कार्बनिक रसायन · Questions 1–10 of 50
Which of the following describes the ability of carbon atoms to form long chains with other carbon atoms?
Correct Answer: A. Catenation
• **Catenation** = carbon's unique ability to form stable C-C covalent bonds with itself. • **Chain formation** — allows carbon to create long-chain molecules and complex structures. • 💡 Wrong-option analysis: Ionization: electron loss/gain process; Isomerism: compounds with same formula, different structure; Electronegativity: attraction for electrons in bonds.
What is the general formula for the homologous series of Alkenes?
Correct Answer: C. CnH2n
• **CnH2n** = alkene formula with one C=C double bond reducing hydrogen count. • **Unsaturation** — carbon-carbon double bond makes alkenes more reactive than alkanes. • 💡 Wrong-option analysis: CnH2n+2: alkane formula with only single bonds; CnHn: not a standard homologous series formula; CnH2n-2: alkynes with triple bond.
Which organic compound is commonly known as 'Marsh Gas'?
Correct Answer: A. Methane
• **Methane (CH₄)** = produced by anaerobic decomposition of organic matter in swamps. • **Biological source** — generated by bacteria in wetlands, rice paddies, and digestive systems. • 💡 Wrong-option analysis: Butane: C₄H₁₀, heavier hydrocarbon; Propane: C₃H₈, used as fuel; Ethane: C₂H₆, not significantly produced in marshes.
The reaction of an alcohol with a carboxylic acid to form a fruity-smelling compound is called?
Correct Answer: A. Esterification
• **Esterification** = alcohol + carboxylic acid → ester + water (Fischer esterification). • **Fruity odors** — esters have pleasant aromas, used in flavorings and fragrances. • 💡 Wrong-option analysis: Hydrogenation: adding H₂ to unsaturated compounds; Polymerization: linking monomers into long chains; Saponification: ester hydrolysis with base.
Which scientist disproved the 'Vital Force Theory' by synthesizing urea in a laboratory?
Correct Answer: B. Friedrich Wöhler
• **Friedrich Wöhler** = synthesized urea (NH₂CONH₂) from ammonium cyanate in 1828. • **Vital Force Theory debunked** — proved organic compounds could be made without living organisms. • 💡 Wrong-option analysis: Dmitri Mendeleev: created periodic table; John Dalton: atomic theory; Antoine Lavoisier: law of conservation of mass.
What is the hybridisation of carbon atoms in a diamond crystal?
Correct Answer: D. sp3
• **sp³ hybridization** = each carbon atom bonds to 4 other carbons in tetrahedral geometry. • **Diamond structure** — creates strong 3D network, making diamond extremely hard material. • 💡 Wrong-option analysis: sp: linear bonding, two bonds per atom; sp²: trigonal planar, three bonds (like graphite); dsp²: square planar geometry, different structure.
Which of the following functional groups is characteristic of organic aldehydes?
Correct Answer: D. -CHO
• **Aldehyde group (-CHO)** = carbonyl carbon bonded to H and another carbon or group. • **Chemical reactivity** — aldehydes are easily oxidized to carboxylic acids, reduce Tollens reagent. • 💡 Wrong-option analysis: -COOH: carboxylic acid, two oxygens; -CO-: ketone carbonyl between two carbons; -OH: hydroxyl, alcohol or phenol group.
Which hydrocarbon gas is used for the artificial ripening of green fruits?
Correct Answer: C. Ethylene
• **Ethylene (C₂H₄)** = plant hormone that triggers ripening cascade in fruits. • **Agricultural application** — used to artificially ripen bananas, tomatoes, and mangoes. • 💡 Wrong-option analysis: Ethane: C₂H₆ saturated hydrocarbon, no ripening activity; Methane: CH₄, inert simple alkane; Acetylene: C₂H₂ alkyne, not a ripening agent.
The industrial process of converting vegetable oils into vanaspati ghee involves?
Correct Answer: D. Hydrogenation
• **Hydrogenation** = Hydrogenation adds hydrogen to unsaturated fats in the presence of a nickel catalyst. • (Contextual detail from explanation) • 💡 Wrong-option analysis: A: Hydrolysis; B: Oxidation; C: Fermentation
Which organic acid is primarily found in vinegar?
Correct Answer: C. Acetic acid
• **Acetic acid** = Vinegar is a dilute solution of acetic acid, typically containing 4% to 8% by volume. • (Contextual detail from explanation) • 💡 Wrong-option analysis: A: Citric acid; B: Lactic acid; D: Formic acid