Chemistry
Organic Chemistry Fundamentals
287 Questions
Organic chemistry fundamentals cover the structure, properties, and reactions of carbon containing compounds. The questions explore functional groups, isomerism, homologous series, and basic reaction mechanisms. This forms the basis of general chemistry across multiple examination formats.
Functional groupsIsomerism typesHomologous seriesCycloalkanesOrganic monomers
Organic Chemistry Fundamentals Questions
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Plannar chirality
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Axial chirality
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Supramolecular chirality
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Inherent chirality
B
Correct answer
Explanation
Axial chirality is a special case of chirality in which a molecule does not possess a stereogenic centre (the most common form of chirality in organic compounds) but an axis of chirality - an axis about which a set of substituents is held in a spatial arrangement that is not superposable on its mirror image
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Indazole
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Benzimidazole
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Purine
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Pyrazole
C
Correct answer
Explanation
A purine is a heterocyclic aromatic organic compound, consisting of a pyrimidine ring fused to an imidazole ring. Purines, including substituted purines and their tautomers, are the most widely distributed kind of nitrogen-containing heterocycle in nature.
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Indole
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Isoindole
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Isoindene
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Indene
D
Correct answer
Explanation
Indene is a flammable polycyclic hydrocarbon. It is composed of a benzene ring fused with a cyclopentene ring. This aromatic liquid is colourless although samples often are pale yellow. The principal industrial use of indene is in the production of indene/coumarone thermoplastic resins.
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Thiophene
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Benzothiophene
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Dibenzothiophene
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Biphenyl
C
Correct answer
Explanation
Dibenzothiophene is the organosulfur compound consisting of two benzene rings fused to a central thiophene ring. It is a colourless solid .This tricyclic heterocycle, and especially its alkyl substituted derivatives, occur widely in heavier fractions of petroleum.
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Phenylphosphine
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Phosgene
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Phosphine
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Phosphite
A
Correct answer
Explanation
Phenylphosphine is a primary phosphine. It is the phosphorus analog of aniline. Like all other primary phosphines, phenylphosphine has an intense penetrating odour. It is highly oxidizable, it can function as ligands in complexes, and it is highly nucleophilic.
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Nuclear magnetic resonance
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Elemental analysis
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Mass spectrometry
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Crystallography
D
Correct answer
Explanation
Crystallography is an unambiguous method for determining molecular geometry, the proviso being that single crystals of the material must be available and the crystal must be representative of the sample. Highly automated software allows a structure to be determined within hours of obtaining a suitable crystal.
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Polyfluorenes
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The phenylene group
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Pyrene
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Azulene
D
Correct answer
Explanation
Azulene is an organic compound and an isomer of naphthalene.
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chain
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position
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functional
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geometrical
C
Correct answer
Explanation
Alkenes and cycloalkanes have the same molecular formula (CnH2n). Since cycloalkanes do not behave as unsaturated hydrocarbons, alkenes and cycloalkanes are termed functional isomers. For instance, propene is isomeric with cyclopropane (or trimethylene).
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Hentriacontane
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Nonacosane
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Tetracosane
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Icosane
B
Correct answer
Explanation
Nonacosane is a straight-chain hydrocarbon. It has 1,590,507,121 constitutional isomers. Nonacosane has been reported to be a component of a pheromone of Orgyia leucostigma, and evidence suggest it plays a role in the chemical communication of several insects, including the female Anopheles stephensi mosquito.
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2-Methylpentane
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3-Methylpentane
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2,3-Dimethylbutane
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2,2-Dimethylbutane
D
Correct answer
Explanation
2,2-Dimethylbutane, trivially known as neohexane, is an organic compound with formula C6H14 or (H3C-)3-C-CH2-CH3. It is therefore an alkane, indeed the most compact and branched of the hexane isomers — the only one with a quaternary carbon and a butane (C4) backbone.
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oxetane
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thietane
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dioxetane
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dithietane
B
Correct answer
Explanation
Thietane is a heterocyclic compound containing a saturated four-membered ring with three carbon atoms and one sulphur atom.
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azete
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oxetene
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thiete
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dithietes
C
Correct answer
Explanation
Thiete is a heterocycle. It is more commonly encountered not on its own, but in anellated derivatives, several of which have been synthesized. Thietes are generally not very stable.
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atropisomers
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cis/trans- isomerism
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conformational isomerism
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optical isomerism
A
Correct answer
Explanation
Atropisomers are stereoisomers resulting from hindered rotation about single bonds where the steric strain barrier to rotation is high enough to allow for the isolation of the conformers.
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Diastereomers
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Racemic mixture
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Enantiomer
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Conformers
D
Correct answer
Explanation
Conformational isomerism is a form of stereoisomerism in which the isomers can be interconverted exclusively by rotations about formally single bonds. Such isomers are generally referred to as conformational isomers or conformers and specifically as rotamers when they differ by rotation about only one single bond.
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Twist-boat
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Half-chair
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Boat
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Chair
D
Correct answer
Explanation
Chair conformations are the most accurate representations of how cyclohexane rings are actually oriented in space. They appropriately reflect the angles between the carbons in the ring and the positions of the groups on each carbon in the ring.