Which of the following best describes an acid according to the Brønsted-Lowry theory?

A. A substance that donates a proton.

B. A substance that accepts a proton.

C. A substance that donates an electron.

D. A substance that accepts an electron.

What is the conjugate base of H2O when it acts as an acid?

A. OH-

B. H3O+

C. H2O

D. H+

Which of the following is NOT a limitation of the Arrhenius theory of acids and bases?

A. It only applies to aqueous solutions.

B. It does not explain the acidic behaviour of substances like NH3.

C. It defines acids as proton donors.

D. It is based on the formation of ions.

In the reaction: NH3 + H2O -> NH4+ + OH-, which species is the acid?

A. NH3

B. H2O

C. NH4+

D. OH-

Which of the following pairs represents a conjugate acid-base pair?

A. H2O and H3O+

B. H2O and OH-

C. H+ and OH-

D. H2O and H2O

a) Define an acid and a base according to the Brønsted-Lowry theory. [2]

b) Given the reaction: NH3 + H2O -> NH4+ + OH-, identify the conjugate acid-base pairs. [2]

a) Describe the limitations of the Arrhenius theory of acids and bases. [3]

b) How does the Brønsted-Lowry theory overcome these limitations? [2]

a) Given the equation: HCl + H2O -> H3O+ + Cl-, explain the acid-base behaviour in terms of proton transfer. [2]

b) If the concentration of H3O+ ions in the solution is 0.01 M, calculate the pH of the solution. [2]

a) Describe the difference between a strong acid and a weak acid in terms of their degree of ionisation. [3]

b) Given that acetic acid (CH3COOH) is a weak acid, explain its behaviour when dissolved in water. [2]

c) Why is the pH of a 0.1 M solution of hydrochloric acid (HCl) lower than that of a 0.1 M solution of acetic acid? [2]

a) Define a conjugate acid-base pair and provide an example. [2]

b) If the concentration of OH- ions in a solution is 0.001 M, calculate the pOH of the solution. [2]

c) How can you determine the pH of the solution using the pOH value? [2]

Which statement about the Lewis theory of acids and bases is correct?

A. It defines acids as proton donors.

B. It is limited to aqueous solutions.

C. It defines acids as electron pair acceptors.

D. It defines bases as proton donors.

For the reaction: HCl + H2O -> H3O+ + Cl-, what is the role of H2O?

A. Acid

B. Base

C. Salt

D. Neutral substance

Which of the following is a characteristic of a system at equilibrium?

A. The concentrations of reactants and products are equal.

B. The forward reaction has stopped.

C. The rate of the forward reaction equals the rate of the reverse reaction.

D. The reaction has reached completion.

Which of the following is NOT true about the conjugate acid-base pairs?

A. They differ by a proton.

B. They are present in the same reaction.

C. They have the same charge.

D. They are related by the transfer of a proton.

In the reaction: CH3COOH -> CH3COO- + H+, which species is the conjugate base of CH3COOH?

A. CH3COO-

B. H+

C. CH3COOH

D. None of the above

a) What is the significance of Ka in acid-base equilibria? [3]

b) If a weak acid has a larger Ka value compared to another weak acid, what does this indicate about its strength? [2]

c) How does the value of Ka relate to the pH of a weak acid solution? [2]

a) What is meant by the term "buffer solution"? [2]

b) Describe the mechanism of buffer action when a small amount of acid is added to the buffer solution. [3]

c) Why is it important to choose a weak acid or base and its salt when preparing a buffer solution? [2]

a) Define the term "acid" based on the Brønsted-Lowry theory. [2]

b) If H2SO4 donates a proton to another substance, what is the resulting species called? [2]

c) Explain the concept of a "conjugate acid-base pair" using the reaction between H2O and NH3. [3]

d) Why is water considered amphoteric in nature? [2]

a) What is the significance of the value of Kb in relation to bases? [2]

b) Given that ammonia (NH3) is a weak base, how does it behave when dissolved in water? [3]

c) How is the relationship between Ka and Kb for a conjugate acid-base pair expressed mathematically? [3]

d) If a solution has a pOH of 5, what would be its pH? [2]

a) Describe the limitations of the Arrhenius theory of acids and bases. [3]

b) How does the Lewis theory of acids and bases differ from the Brønsted-Lowry theory? [3]

c) If a substance is a Lewis acid, what characteristic must it possess? [2]

d) Provide an example of a reaction that can be explained using the Lewis theory but not the Brønsted-Lowry theory. [3]