Question 1

Which of the following statements best explains why the conjugate base of a carboxylic acid is more stable than the conjugate base of an alcohol?

Accepted Answer

The carboxylate ion is stabilized by resonance, allowing the negative charge to be delocalized over two oxygen atoms.

Question 2

Given the following acid-base reaction:

$\ce{CH3COOH + OH^- -> CH3COO^- + H2O}$

Which direction will the equilibrium favor and why?

Accepted Answer

The equilibrium favors products because the conjugate base $\ce{CH3COO^-}$ is resonance stabilized, making it weaker than $\ce{OH^-}$.

Question 3

Which of the following best describes the geometry and approximate bond angle around a carbon atom with $sp^2$ hybridization?

Accepted Answer

Trigonal planar, $120^\circ$

Question 4

Which of the following is a correct IUPAC name for the compound shown below?

(Structure: Decane backbone with ethyl at C7, isopropyl at C5, and two methyls at C4)

Accepted Answer

7-ethyl-5-isopropyl-4,4-dimethyldecane

Question 5

Which of the following pairs of structures are constitutional isomers?

Accepted Answer

Two molecules with the same molecular formula but different connectivity of atoms.

Question 6

In the resonance structures of a carboxylate ion, which of the following statements is true?

Accepted Answer

Only electrons move; atoms do not move during resonance.

Question 7

Which of the following protons is the most acidic in the molecule below?

(Structure: Benzene ring attached to a carbonyl group, with three protons labeled: one on a methyl group, one on a carbon adjacent to the carbonyl, and one on a carbon attached to a nitrile group)

Accepted Answer

The proton on the carbon adjacent to the nitrile group (sp hybridized carbon).

Question 8

Which of the following best describes the orbitals involved in the $\sigma$ bond between two $sp$ hybridized carbons?

Accepted Answer

$sp$–$sp$ overlap

Question 9

Which of the following is a correct Lewis acid-base reaction?

Accepted Answer

A reaction where a lone pair from a base is donated to an electron-deficient atom (acid), forming a new bond.

Question 10

Which of the following best explains why $sp$ hybridized carbons are more electronegative than $sp^2$ or $sp^3$ hybridized carbons?

Accepted Answer

$sp$ hybridized carbons have more $s$ character, bringing electrons closer to the nucleus.

Question 11

Which of the following is the correct order of stability for the Newman projections of butane (from most stable to least stable)?

Accepted Answer

Anti > Gauche > Eclipsed

Question 12

Which of the following functional groups is present in both methotrexate and sacubitril?

Accepted Answer

Amide

Question 13

Which of the following statements about resonance structures is correct?

Accepted Answer

Resonance structures differ only in the arrangement of electrons, not the arrangement of atoms.

Question 14

Which of the following is NOT a valid resonance structure for the acetate ion ($\ce{CH3COO^-}$)?

Accepted Answer

A structure where the negative charge is placed on the methyl carbon.

Question 15

Which of the following best describes a constitutional isomer?

Accepted Answer

Molecules with the same molecular formula but different connectivity of atoms.

Question 16

Which of the following best explains why the equilibrium in an acid-base reaction favors the formation of the weaker acid and base?

Accepted Answer

The weaker acid and base are more stable, so the reaction proceeds toward their formation.

Question 17

Which of the following is the correct hybridization and geometry for a carbon atom with four single bonds?

Accepted Answer

$sp^3$, tetrahedral

Question 18

Which of the following is the correct total number of $\sigma$ bonds in the methotrexate molecule shown in the exam?

Accepted Answer

$21$

Question 19

Which of the following best describes the effect of hybridization on acidity?

Accepted Answer

The greater the $s$ character in the atom bearing the proton, the more acidic it is.

Organic Chemistry Exam 1 Study Guide: Structure, Bonding, Acids & Bases, and Stereochemistry

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