Question 1

Which of the following best describes a Brønsted-Lowry acid?

Accepted Answer

A species that donates a proton ($H^+$) to another species.

Question 2

Which of the following is the correct relationship between $K_a$ and $pK_a$ for an acid?

Accepted Answer

$pK_a = -\log_{10}(K_a)$

Question 3

Which of the following statements is true regarding acid strength and conjugate base stability?

Accepted Answer

A strong acid has a weak, unreactive conjugate base.

Question 4

Which of the following is a Lewis base?

Accepted Answer

$NH_3$

Question 5

Consider the following reaction: $NH_3 + HCl \rightarrow NH_4^+ + Cl^-$. Which species acts as the Brønsted-Lowry base?

Accepted Answer

$NH_3$

Question 6

Which factor most strongly stabilizes a conjugate base within a group of the periodic table?

Accepted Answer

Atomic size

Question 7

Which of the following acids is expected to be more acidic due to resonance stabilization of its conjugate base?

Accepted Answer

Acetic acid ($CH_3COOH$)

Question 8

Trichloroacetic acid ($CCl_3COOH$) has a much lower $pK_a$ than acetic acid ($CH_3COOH$). What structural effect is primarily responsible for this difference?

Accepted Answer

Inductive effect from electron-withdrawing chlorines

Question 9

Which of the following statements about the inductive effect is correct?

Accepted Answer

Halogens near the acidic hydrogen stabilize the conjugate base and increase acidity.

Question 10

Which of the following is the correct order of prioritization for structural effects on conjugate base stability?

Accepted Answer

Atomic size > Resonance > Electronegativity > Induction > Hybridization

Question 11

Which of the following species is the nucleophile in a Lewis acid-base reaction?

Accepted Answer

The electron pair donor

Question 12

Which of the following statements is true regarding $pK_a$ values?

Accepted Answer

A lower $pK_a$ value indicates a stronger acid.

Question 13

Which of the following molecules will have the most stable conjugate base due to hybridization effects?

Accepted Answer

Ethyne ($C_2H_2$)

Question 14

Which of the following is NOT a correct example of a Lewis acid?

Accepted Answer

$NH_3$

Question 15

In the reaction $NaNH_2 + H_2O \rightarrow Na^+ + NH_3 + OH^-$, which species acts as the Brønsted-Lowry base?

Accepted Answer

$NH_2^-$

Question 16

Which of the following factors increases acidity by stabilizing the conjugate base through electron delocalization?

Accepted Answer

Resonance

Question 17

Which of the following statements best explains why $H_2$ has a high $pK_a$ value?

Accepted Answer

It is a weak acid and does not readily participate in acid-base reactions.

Question 18

Which of the following is the correct arrow-pushing formalism for a Brønsted-Lowry acid-base reaction?

Accepted Answer

The arrow starts at the electron pair of the base and points toward the acidic proton.

Question 19

Which of the following is the best explanation for why $Cl^-$ is a more stable base than $OH^-$?

Accepted Answer

Chlorine is larger than oxygen, allowing better charge delocalization.

Chapter 4 – Acids & Bases/Electron Flow: General Chemistry Study Notes

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