Free Fundamental Principles of Organic Chemistry MCQs with Answers
536 Fundamental Principles of Organic Chemistry MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Organic chemistry begins with carbon compounds classified by carbon skeleton, saturation and functional group. Work includes identifying groups such as hydroxyl, carbonyl, carboxyl and amino, applying basic nomenclature, and distinguishing structural, geometric and optical isomers, where the same molecular formula does not necessarily mean the same structure or properties.
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Read the Fundamental Principles of Organic Chemistry notesFree MDCAT chapter notes with key terms536 questions · page 8 of 27
- A. Benzene
- B. Nitrobenzene
- C. Toluene
- D. Alkene
Explanation: The Friedel-Crafts reaction is a type of electrophilic aromatic substitution reaction.
Correct answer: Toluene- A. Alternate double bonds
- B. Electrons' cloud
- C. Double bonds
- D. Delocalization of electrons
Explanation: Benzene's stability is attributed to the delocalization of electrons in its pi system.
Correct answer: Delocalization of electrons- A. C6H5CHO
- B. C6H5CH2OCC6H5
- C. C6H5CH2OH
- D. C3H5N
Explanation: Benzyl alcohol is an aromatic alcohol with the formula C6H5CH2OH. It consists of a benzene ring (C6H5) attached to a methylene group (CH2)…
Correct answer: C6H5CH2OH- A. They have low boiling points
- B. They are more soluble in non-polar solvents
- C. They show polymorphism and isomorphism
- D. They are flammable.
Explanation: Polymorphism and isomorphism, which relate to different crystal structures, are characteristic of ionic and inorganic solids.
Correct answer: They show polymorphism and isomorphism- A. Pyrrole
- B. Resorcinol
- C. Furan
- D. Thiophene
Explanation: A heterocyclic compound contains atoms of at least two different elements in its ring structure.
Correct answer: Resorcinol- A. Isomerism
- B. Complexity of structure
- C. Catenation
- D. Homologous series
Explanation: Catenation is the unique ability of carbon atoms to form strong covalent bonds with other carbon atoms, creating long chains and complex…
Correct answer: Catenation- A. Alkyne
- B. Alkane
- C. Benzene
- D. Alkene
Explanation: Alkanes are saturated hydrocarbons containing only strong, non-polar carbon-carbon and carbon-hydrogen single bonds (sigma bonds).
Correct answer: Alkane- A. They are non-polar molecules
- B. They have high boiling points
- C. They are symmetrical molecules
- D. They have high melting points
Explanation: Trans isomers are generally more symmetrical, which often leads to them being non-polar.
Correct answer: They have high boiling points- A. 2-Butene
- B. 3-Hexene
- C. 2-Pentene
- D. 1-Butene
Explanation: For geometric (cis-trans) isomerism to exist, each carbon atom of the double bond must be attached to two different groups.
Correct answer: 1-Butene- A. Having carbon-carbon double bond (C = C)
- B. Different groups are attached with carbon-containing double bond
- C. Double bond involves free rotation
- D. Both A and B
Explanation: Two conditions must be met for a molecule to exhibit geometric isomerism.
Correct answer: Both A and B- A. Cyano group
- B. Formyl group
- C. Mercapto group
- D. Amino group
Explanation: A thioalcohol, also known as a thiol, is the sulfur analogue of an alcohol.
Correct answer: Mercapto group- A. Tautomerism
- B. Metamerism
- C. Geometric isomerism
- D. Chain isomerism
Explanation: Tautomerism is a special type of structural isomerism where two isomers, called tautomers, are in rapid equilibrium with each other.
Correct answer: Tautomerism- A. Metamer
- B. Elastomer
- C. Enantiomer
- D. Tautomer
Explanation: Optical isomers are pairs of molecules that are non-superimposable mirror images of each other.
Correct answer: Enantiomer- A. Isobutane
- B. Isobutylene
- C. Isopentyne
- D. All of these
Explanation: Acyclic compounds are organic compounds that do not contain a ring of atoms; they are open-chain compounds.
Correct answer: All of these- A. Four
- B. Five
- C. Three
- D. Six
Explanation: Butanol (C₂H₂OH) has four structural isomers. These are butan-1-ol, butan-2-ol, 2-methylpropan-1-ol (isobutanol), and 2-methylpropan-2-ol…
Correct answer: Four- A. C10H22
- B. CH3CHO
- C. CHCl3
- D. CH3CH2O
Explanation: C10H22 is a non-polar hydrocarbon because it contains only C-C and C-H bonds.
Correct answer: C10H22- A. R-O-R
- B. R-Se-R
- C. R-S-R
- D. R-Te-R
Explanation: A thioether is the sulfur analogue of an ether. In its structure, the oxygen atom of an ether is replaced by a sulfur atom, giving the…
Correct answer: R-S-R- A. -NH2
- B. C=NH
- C. -CN
- D. -C-NH2
Explanation: The amino functional group consists of a nitrogen atom bonded to hydrogen atoms and/or carbon atoms.
Correct answer: -NH2- A. Phenol..... Ar-OH
- B. Ketone.......R-COR
- C. Carboxylic acid....... RCOOH
- D. Aldehyde... ROR
Explanation: The general formula R-O-R' represents an ether. The general formula for an aldehyde is R-CHO, where a carbonyl group is bonded to at least…
Correct answer: Aldehyde... ROR- A. Ketone / aldehyde
- B. Aldehyde / alkane
- C. Ketone / alkane
- D. Aldehyde / acid
Explanation: When a primary alcohol is oxidized, it forms an aldehyde; when a secondary alcohol is oxidized, it forms a ketone.
Correct answer: Ketone / aldehyde