Question 1

According to the Brønsted-Lowry definition, which of the following best describes an acid?

Accepted Answer

A substance that donates a proton ($$H^+) in a $$chemical reaction.

Question 2

Which of the following molecules will have the most stable conjugate base due to resonance stabilization?

Accepted Answer

$$CH_3COOH$$

Question 3

Why is the negative charge on the acetate ion ($$CH_3COO^-) $$more stable than on the ethoxide ion ($$CH_3CH_2O^-$$)?

Accepted Answer

Because the negative charge on acetate is delocalized by resonance between two oxygen atoms.

Question 4

Which of the following acids is the strongest, based on the electronegativity of the atom bearing the negative charge?

Accepted Answer

$$HF$$

Question 5

Consider the following acid-base reaction: $$CH_3CH_2OH + KOH \rightarrow$$ Which product is formed?

Accepted Answer

$$CH_3CH_2O^- + H_2O$$

Question 6

Which factor best explains why $$HSO_4$$^-$$ is a weaker acid than H_2SO_4$?

Accepted Answer

The additional negative charge on $$HSO_4$$^-$$ makes it less likely to lose another proton.

Question 7

Which of the following molecules is most acidic due to the inductive effect of a nearby electronegative atom?

Accepted Answer

$$CF_3COOH$$

Question 8

Which of the following is the most basic species?

Accepted Answer

$$NaNH_2$$

Question 9

Which of the following statements about the relationship between acid strength and conjugate base stability is correct?

Accepted Answer

A strong acid has a highly stable conjugate base.

Question 10

Which of the following molecules has the most acidic proton due to hybridization effects?

Accepted Answer

$$HC \equiv CH$$

Question 11

Which of the following is the correct mechanism for the deprotonation of phenol ($$C_6H_5OH) by$$ $$NaOH$$?

Accepted Answer

$$C_6H_5OH + OH^- \rightarrow C_6H_5O^- + H_2O$$

Question 12

Which of the following best explains why $$H_2S is a $$stronger acid than $$H_2O$$?

Accepted Answer

Sulfur is larger than oxygen and can better stabilize the negative charge.

Question 13

Which of the following bases is most likely to stabilize a negative charge after accepting a proton?

Accepted Answer

A base with a lone pair on a highly electronegative atom.

Question 14

Which of the following pairs correctly matches the acid with its conjugate base?

Accepted Answer

$$H_2SO_4$$ and $$HSO_4$$^-$$

Question 15

Which molecule is more acidic: $$CH_3CH_2OH or$$ $$C_6H_5OH$$? Why?

Accepted Answer

$$C_6H_5OH is $$more acidic because its conjugate base is stabilized by resonance.

Question 16

Which of the following is the strongest acid based on the provided pKa values?

Accepted Answer

$$HBr ($$pKa \u003c -4)

Question 17

Which of the following bases is stronger: $$NaOH or$$ $$H_2O$$? Why?

Accepted Answer

$$NaOH is $$stronger because it contains $$OH^-$$, which has a negative charge and is more eager to accept a proton.

Question 18

Which of the following molecules is most basic?

Accepted Answer

$$NaNH_2$$

Question 19

Which of the following statements about resonance and acidity is correct?

Accepted Answer

Resonance stabilization of the conjugate base increases the acidity of the acid.

Acids and Bases in Organic Chemistry: Concepts, Mechanisms, and Trends

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