Q: A 0.015 M solution of HCl is prepared. What is the $$[OH^-] in $$this solution at 25°C?

$$\mathrm{[OH^-] = 1.0 \times 10$$^{-14}$$ / 0.015 \; M}$$

Question 1

Which of the following statements best describes the relationship between CH3COOH and CH3COO– in the reaction: $$\mathrm{CH_3COOH(aq) + H_2O(l) \rightleftharpoons CH_3COO^-(aq) + H_3O^+(aq)}$$?

Accepted Answer

CH3COOH is an acid and CH3COO– is its conjugate base.

Question 2

In the reaction $$\mathrm{NH_3$(aq) + H_2O(l) \rightleftharpoons NH_4$^+(aq) + OH^-(aq)}$$, which species acts as the Brønsted-Lowry base?

Accepted Answer

NH3

Question 3

Given the reaction $$\mathrm{CH_3COOH + H_2O \rightleftharpoons CH_3COO^- + H_3O^+}$$, which pair represents a conjugate acid-base pair?

Accepted Answer

CH3COOH and CH3COO–

Question 4

Which of the following best describes the self-ionization of water?

Accepted Answer

$$\mathrm{2H_2O(l) \rightleftharpoons H_3O^+(aq) + OH^-(aq)}$$

Question 5

A solution has $$[H_3O^+] = 1.0 	imes 10$$^{-7}$$ M at 25°C. What is its pH?

Accepted Answer

$$\mathrm{pH = 7}$$

Question 6

Which of the following is a strong acid according to Table 16.3?

Accepted Answer

HCl

Question 7

If the pH of a solution is 4.5, what is the concentration of $$\mathrm{H_3O^+}$$?

Accepted Answer

$$\mathrm{[H_3O^+] = 10$$^{-4.5}$$ \; M}$$

Question 8

Which of the following statements is true for a basic solution at 25°C?

Accepted Answer

$$\mathrm{[H_3O^+] \u003c [OH^-]}$$

Question 9

Which of the following is the correct expression for the acid dissociation constant ($$K_a) $$for acetic acid?

Accepted Answer

$$\mathrm{K_a = \frac{[CH_3COO^-][H_3O^+]}{[CH_3COOH]}}$$

Question 10

A 0.015 M solution of HCl is prepared. What is the $$[OH^-] in $$this solution at 25°C?

Accepted Answer

$$\mathrm{[OH^-] = 1.0 	imes 10$$^{-14}$$ / 0.015 \; M}$$

Question 11

Which of the following best explains why HF is a weaker acid than HCl, HBr, and HI?

Accepted Answer

HF forms strong hydrogen bonds, making its ionization less favorable.

Question 12

Which factor increases the strength of an oxoacid?

Accepted Answer

High number of terminal oxygen atoms.

Question 13

What is the relationship between $$K_a$$ and $$K_b$$ for a conjugate acid-base pair?

Accepted Answer

$$\mathrm{K_a \cdot K_b = K_w}$$

Question 14

A polyprotic acid, such as H3PO4, ionizes in three steps. Which statement is correct about its ionization constants?

Accepted Answer

Ka1 \u003e Ka2 \u003e Ka3

Question 15

Which of the following is a Lewis acid?

Accepted Answer

BF3

Question 16

If the degree of ionization ($$\alpha) of a $$weak acid increases as its concentration decreases, which of the following best explains this behavior?

Accepted Answer

The equilibrium shifts to produce more ions as the acid is diluted.

Question 17

Which of the following solutions will be acidic at 25°C?

Accepted Answer

NH4NO3(aq)

Question 18

A solution of 0.1 M acetic acid ($$\mathrm{CH_3COOH}) $$has a $$K_a of$$ $$1.8 	imes 10$$^{-5}$$. What is the percent ionization?

Accepted Answer

1.34%

Question 19

Which of the following is the correct formula for calculating pOH?

Accepted Answer

$$\mathrm{pOH = -\log[OH^-]}$$

Acid-Base Equilibria: Concepts, Calculations, and Molecular Structure

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