MCAT Organic Chemistry: Nomenclature Practice

Introduction

• Lecturer: Iman
• Topic: Practice problems on nomenclature for MCAT organic chemistry.

Problem 1: Names of Ethanal, Methanal, and Ethanol

• Ethanal:
  • 2 carbons + aldehyde group.
  • Common name: Acetaldehyde.
• Methanal:
  • 1 carbon + aldehyde group.
  • Common name: Formaldehyde.
• Ethanol:
  • 2 carbons + hydroxyl group (alcohol).
  • Common name: Ethyl alcohol.
• Answer Choice: Acetaldehyde, formaldehyde, ethyl alcohol (Answer: A).

Problem 2: Terminal Functional Groups

• Terminal Functional Groups:
  • Aldehydes: End of carbon chain.
  • Carboxylic Acids: End of carbon chain.
  • Ketones: Internal, carbon on both sides of the carbonyl.
• Answer: Aldehydes and Carboxylic Acids (Answer: C).

Problem 3: Parent Root Name

• Given molecule with carboxylic acid and aldehyde groups.
• Highest Priority Group: Carboxylic Acid -> suffix "-oic acid".
• Carbon Chain: 3 carbons.
• Name: Propanoic Acid (Answer: C).

Problem 4: Highest Priority Functional Group

• Molecule: Anhydride (Dividing the middle, both sides equal).
• Functional Group: Anhydride.
• Name for Practice: Propanoic Anhydride.
• Answer: Anhydride (Answer: C).

Problem 5: IUPAC Name Suffix

• Functional Groups in the given molecule:
  • Alcohol: OH group.
  • Halogen: X group.
  • Alkene: Double bond.
  • Alkyne: Triple bond.
  • Ether.
  • Carboxylic Acid.
• Highest Priority Functional Group: Carboxylic Acid -> suffix "-oic acid".
• Answer: "oic acid" (Answer: C).

Problem 6: Correctly Numbered Carbon Backbone

• Numbering Scheme 1: First substituent at 3 and second at 4.
• Numbering Scheme 2: First substituent at 2 and second at 3.
• Longest Carbon Chain: 6 carbons (Correct: Scheme 1).
• Answer: Numbering Scheme 1 (Answer: A).

Problem 7: Structure for 2,3-Dihydroxybutane dioic acid (Tartaric Acid)

• Butane: 4 carbon chain.
• Dihydroxy: Hydroxyl groups at position 2 and 3.
• Dioic Acid: Carboxylic acids at both ends.
• Answer: B.

Problem 8: Common Names and Prefix

• One Carbon Aldehyde and Carboxylic Acid:
  • Aldehyde: Methanal (Formaldehyde).
  • Carboxylic Acid: Methanoic Acid (Formic Acid).
• Prefix: Form.
• Answer: B.

Problem 9: IUPAC Name Determination

• Longest Carbon Chain: 7 carbons -> Heptane.
• Substituents: Methyl groups at 2 and 5.
• Name: 2,5-dimethyl heptane.
• Answer: A.

Problem 10: Correct IUPAC Name Selection

• Longest Carbon Chain: 6 carbons -> Hexane.
• Substituents: Two methyl groups at position 2 and 5, ethyl group at 3.
• Name in Alphabetical Order:
  • 3-ethyl-2,2,5-trimethyl hexane.
• Answer: D.

Problem 11: Prefix Selection from IUPAC Name

• Structure: 4 carbons with an alcohol at position 2 and methyl at position 2.
• Name: 2-methyl-2-butanol.
• Answer: B.

Problem 12: Functional Groups in NADH

• Name Indicators:
  • Nicotinamide (amide functional group).
  • Diphospho (two phosphate groups).
• Answer: C.

Problem 13: Structure of Pyruvic Acid

• Common Name: Acetylformic acid.
  • "Acetyl": Two-carbon unit with a carbonyl group.
  • "Formic acid": Single carbon carboxylic acid.
• Structure: Three carbons, carbonyl and carboxylic acid.
• Answer: A.

Problem 14: Correct IUPAC Name for 2,3-Diethylpentane

• Structure Drawn: Longest chain is hexane (6 carbons).
• Substituents: Methyl at position 4 and ethyl group at 3.
• Name: 3-ethyl-4-methyl hexane.
• Correction: C.