Question 1

Which of the following molecules has a net dipole moment of zero?

Accepted Answer

Carbon dioxide ($$CO_2)$$

Question 2

Which of the following statements about resonance structures is correct?

Accepted Answer

The true structure of a molecule is a hybrid of all possible resonance structures.

Question 3

Which of the following is the correct condensed structural formula for butane?

Accepted Answer

$$CH_3CH_2CH_2CH_3$$

Question 4

Which of the following is the conjugate base of acetic acid ($$CH_3COOH$$)?

Accepted Answer

$$CH_3COO^-$$

Question 5

A molecule has the following Newman projection: front carbon has $$CH_3$$, $$H$$, and $$Cl$$; back carbon has $$CH_3$$, $$H$$, and $$Br. $$Which of the following best describes the relationship between the two $$CH_3$$ groups in the staggered conformation?

Accepted Answer

They are anti to each other ($$180^	ext{o}$$ apart).

Question 6

Which of the following is NOT a valid criterion for a molecule to be chiral?

Accepted Answer

The molecule must be superimposable on its mirror image.

Question 7

Which of the following is the most acidic proton in acetone ($$CH_3COCH_3$$)?

Accepted Answer

The hydrogen atoms on the methyl groups adjacent to the carbonyl.

Question 8

Which of the following best describes the hybridization of the central carbon atom in ethene ($$C_2H_4$$)?

Accepted Answer

$$sp^2$$

Question 9

Which of the following molecules is achiral?

Accepted Answer

2-chloropropane

Question 10

Which of the following is the correct Lewis structure for ammonia ($$NH_3$$)?

Accepted Answer

Nitrogen with three single bonds to hydrogen and one lone pair.

Question 11

Which of the following statements about cis-trans isomerism in alkenes is correct?

Accepted Answer

Cis-trans isomerism occurs when each carbon of the double bond has two different substituents.

Question 12

Which of the following best explains why $$NH_3 is $$more basic than $$H_2O$$?

Accepted Answer

Nitrogen is less electronegative than oxygen, making its lone pair more available for protonation.

Question 13

Which of the following is the correct order of acidity for the following compounds: phenol, ethanol, acetic acid?

Accepted Answer

$$CH_3COOH \u003e C_6H_5OH \u003e C_2H_5OH$$

Question 14

Which of the following is a correct statement about formal charge?

Accepted Answer

Formal charge is calculated by subtracting the number of assigned electrons from the number of valence electrons in the free atom.

Question 15

Which of the following best describes the geometry around the oxygen atom in water ($$H_2O$$)?

Accepted Answer

Bent, with a bond angle of approximately $$104.5^	ext{o}$$

Question 16

Which of the following is the correct IUPAC name for the following structure: $$CH_3CH_2CH_2OH$$?

Accepted Answer

1-Propanol

Question 17

Which of the following statements about Newman projections is correct?

Accepted Answer

Newman projections are used to visualize the conformation of molecules by looking down a specific bond.

Question 18

Which of the following is a correct statement about the relationship between enantiomers?

Accepted Answer

Enantiomers are non-superimposable mirror images of each other.

Question 19

Which of the following is the correct electron-pushing arrow mechanism for the deprotonation of acetic acid by hydroxide ion?

Accepted Answer

Arrow from $$OH^-$$ lone pair to the acidic hydrogen of $$CH_3COOH$$, arrow from $$O-H$$ bond to the oxygen atom of $$CH_3COOH.$$

Organic Chemistry Fundamentals: Structure, Acidity, Conformations, and Stereochemistry

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