Acids, Bases, and Equilibria: Interactive Learning Quizzes for Year 13 Chemistry

Question 1

Identify the factor that would shift the equilibrium of a weak acid dissociation reaction towards the product side.

Accepted Answer

Adding a strong base

Answer

Adding more acid

Answer

Increasing temperature

Answer

Decreasing volume

Question 2

State the primary purpose of a titration.

Accepted Answer

Determining the concentration of an unknown acid or base

Answer

Neutralizing a solution

Answer

Preparing a buffer solution

Answer

Determining the pH of a solution

Question 3

Which indicator is most suitable for titrating a weak acid with a strong base?

Accepted Answer

Phenolphthalein

Answer

Methyl orange

Answer

Litmus

Answer

Congo red

Question 4

Explain the role of Le Chatelier's principle in acid-base equilibria.

Accepted Answer

Predicting the direction of a reaction under stress

Answer

Calculating the equilibrium constant

Answer

Determining the pH of a solution

Answer

Determining the concentration of a solution

Question 5

Define a buffer solution.

Accepted Answer

A solution that resists changes in pH upon addition of small amounts of acid or base

Answer

A solution with a pH of exactly 7.0

Answer

A solution that contains a weak acid and its conjugate base

Answer

A solution that contains a strong acid and its conjugate base

Question 6

Calculate the pH of a 0.10 M solution of HCl in water.

Accepted Answer

0

Answer

1

Answer

2

Answer

7

Question 7

Write the equilibrium constant expression for the reaction N2(g) + 3H2(g) <=> 2NH3(g).

Accepted Answer

K = [NH3]^2/[N2][H2]^3

Answer

K = [N2][H2]^3/[NH3]^2

Answer

K = [N2] + [H2]^3/[NH3]^2

Answer

K = [NH3]^2/[N2] + [H2]^3

Question 8

Predict the effect of adding more reactant to an equilibrium reaction that is exothermic.

Accepted Answer

Equilibrium shifts to the right

Answer

Equilibrium shifts to the left

Answer

No change in equilibrium

Answer

Reaction proceeds faster

Question 9

Identify the strong acid from the following options:

Accepted Answer

Hydrochloric acid

Answer

Acetic acid

Answer

Carbonic acid

Answer

Ammonium hydroxide

Question 10

Calculate the pH of a 0.1 M solution of potassium hydroxide (KOH) at 25°C.

Accepted Answer

13

Answer

1

Answer

7

Answer

14

Question 11

Identify the endothermic process among the following reactions:

Accepted Answer

H2O(l) -> H2O(g)

Answer

NaOH(aq) + HCl(aq) -> NaCl(aq) + H2O(l)

Answer

NH3(g) + HCl(g) -> NH4Cl(s)

Answer

CO2(g) + H2O(l) -> H2CO3(aq)

Question 12

Describe the primary function of a buffer solution:

Accepted Answer

Maintain a relatively constant pH within a specific range

Answer

Neutralize strong acids or bases completely

Answer

Provide a continuous supply of protons

Answer

Catalyze acid-base reactions

Question 13

Determine the hybridization of the nitrogen atom in the ammonium ion (NH4+):

Accepted Answer

sp3

Answer

sp

Answer

sp2

Answer

sp3d

Question 14

Which of the following factors does not affect the position of equilibrium of an acid-base reaction?

Accepted Answer

Pressure

Answer

Initial concentrations of reactants

Answer

Temperature

Answer

Addition of a common ion

Question 15

What is the equivalent point in the acid-base titration for a strong acid and a strong base?

Accepted Answer

Equivalence point

Answer

pH 4

Answer

pH 7

Answer

pH 10

Question 16

Which of the following is not a conjugate acid-base pair?

Accepted Answer

NaOH and HCl

Answer

H2O and OH-

Answer

NH4+ and NH3

Answer

H3O+ and H2O

Question 17

Which of the following is a Lewis acid??

Accepted Answer

H+

Answer

NH3

Answer

OH-

Answer

CH4

Question 18

What is the hybridization of the carbon atom in the H2CO3 molecule?

Accepted Answer

sp3

Answer

sp

Answer

sp2

Answer

sp3d

Question 19

Butanoic acid (CH3CH2CH2COOH) in water has an acid dissociation constant (Ka) of 1.54 x 10^-5. According to Le Chatelier's principle, what will happen to the position of equilibrium if the initial concentration of butanoic acid is doubled?

Accepted Answer

The equilibrium will shift right, increasing the concentration of the butanoate ion.

Answer

The equilibrium will shift left, decreasing the concentration of butanoic acid.

Answer

The equilibrium will remain unchanged.

Question 20

In practical applications, what is the primary purpose of acid-base indicators?

Accepted Answer

Indicating the endpoint of a titration

Answer

Precisely measuring the concentration of an unknown acid or base

Answer

Neutralizing acids or bases in a chemical reaction

Question 21

Identify the conjugate base of NH4+.

Accepted Answer

NH3

Answer

NH2-

Answer

NH4OH

Answer

N2H4

Question 22

Which species is the conjugate acid of NH3?

Accepted Answer

NH4+

Answer

NH2-

Answer

H3O+

Answer

OH-

Question 23

Identify the weak base among the following options.

Accepted Answer

NH3

Answer

NaOH

Answer

KOH

Answer

HCl

Question 24

Write the equilibrium constant expression for the dissociation of HA in water: HA(aq) + H2O(l) ⇌ H3O+(aq) + A-(aq).

Accepted Answer

Ka = [H3O+][A-]/[HA]

Answer

Ka = [HA]/[H3O+][A-]

Answer

Ka = [A-]/[HA]

Answer

Ka = [H3O+]/[HA]

Question 25

Describe the primary function of a buffer solution.

Accepted Answer

To maintain a relatively constant pH despite the addition of acids or bases

Answer

To act as a strong acid or base

Answer

To increase the rate of a reaction

Answer

To decrease the solubility of a substance

Question 26

Identify the Lewis acid in the following reaction: NH3 + H+ ⇌ NH4+

Accepted Answer

H+

Answer

NH3

Answer

NH4+

Answer

OH-

Question 27

Which property is considered a colligative property?

Accepted Answer

Boiling point elevation

Answer

Solubility

Answer

Density

Answer

Color

Question 28

Buffer solutions resist pH changes when small amounts of acid or base are added due primarily to:

Accepted Answer

Common ion effect

Answer

Neutralization reactions

Answer

Formation of a salt

Answer

High concentration of hydrogen ions

Question 29

What is the conjugate acid of H2O?

Accepted Answer

H3O+

Answer

H2

Answer

O2-

Answer

OH-

Question 30

Which type of reaction can be identified by the production of water?

Accepted Answer

Acid-base reaction

Answer

Combustion reaction

Answer

Precipitation reaction

Answer

Redox reaction

Question 31

What is the equilibrium constant expression for the reaction: H2O + CO2 ⇌ H2CO3?

Accepted Answer

Ka = [H2CO3]/[H2O][CO2]

Answer

Kc = [H2CO3]/[H2O]+[CO2]

Answer

Kd = [H2O][CO2]/[H2CO3]

Answer

Kp = [H2CO3]/[H2O][CO2]

Question 32

What is the purpose of using an indicator in a titration?

Accepted Answer

To signal the endpoint of the reaction

Answer

To neutralize the solution

Answer

To increase the accuracy of the measurement

Answer

To catalyze the reaction

Question 33

According to the Brønsted-Lowry definition, what is an acid?

Accepted Answer

A substance that donates a proton (H+)

Answer

A substance that dissolves in water to form a solution with a pH less than 7

Answer

A substance that produces hydroxide ions (OH-) in solution

Answer

A substance that accepts a proton (H+)

Question 34

If the pH of a solution is 3, what is the concentration of hydrogen ions (H+) in moles per cubic decimeter (mol/dm³)?

Accepted Answer

1 x 10^-3 mol/dm³

Answer

1 x 10^3 mol/dm³

Answer

1 x 10^-11 mol/dm³

Answer

3 mol/dm³

Question 35

Which of the following is a characteristic of a weak acid?

Accepted Answer

It only partially ionizes in solution.

Answer

It reacts readily with bases to form salts and water.

Answer

It completely ionizes in solution.

Answer

It produces a high concentration of hydrogen ions in solution.

Question 36

The equilibrium constant for the ionization of a weak acid in water, represented by the equation: CH₃COOH(aq) + H₂O(l) <=> H₃O⁺(aq) + CH₃COO⁻(aq), is denoted by:

Accepted Answer

Ka

Answer

Kw

Answer

Kb

Answer

Kc

Question 37

What is the primary function of a buffer solution?

Accepted Answer

To resist changes in pH upon addition of small amounts of acid or base

Answer

To neutralize a strong acid or base completely

Answer

To increase the pH of a solution

Answer

To decrease the pH of a solution

Question 38

The Henderson-Hasselbalch equation is used to calculate:

Accepted Answer

The pH of a buffer solution

Answer

The concentration of hydrogen ions in a solution

Answer

The pKa of a weak acid

Answer

The equilibrium constant for a weak acid