Q15.40. Give three examples of molecules or ions that are Brønsted–Lowry bases but not Arrhenius bases.

Background

Topic: Acid-Base Theories

This question tests your understanding of the differences between the Brønsted–Lowry and Arrhenius definitions of bases. Brønsted–Lowry bases accept protons (H+), while Arrhenius bases produce OH− in water.

Key Terms:

• Brønsted–Lowry base: Proton acceptor

• Arrhenius base: Produces OH− in aqueous solution

Step-by-Step Guidance

1. Recall that Brønsted–Lowry bases can be any species that accepts a proton, not just those that produce OH−.

2. Think of molecules or ions that can accept a proton but do not release OH− when dissolved in water.

3. Consider examples such as ammonia (NH3), anions like HCO3−, or other weak bases.

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Q15.41. Give an example of an anion that can behave both as a Brønsted–Lowry acid and as a Brønsted–Lowry base.

Background

Topic: Amphiprotic Species

This question is about amphiprotic ions, which can act as both acids (donate H+) and bases (accept H+).

Key Terms:

• Amphiprotic: Can act as both acid and base

• Brønsted–Lowry acid: Proton donor

• Brønsted–Lowry base: Proton acceptor

Step-by-Step Guidance

1. Recall common ions that have hydrogen and can both donate and accept a proton.

2. Think about ions like HCO3− or HSO4−.

3. Check if the ion can lose a proton (acid) and gain a proton (base).

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Q15.42. Give the formula for the conjugate base of each of the following Brønsted–Lowry acids:

• (a) HSO4−

• (b) H2SO3

• (c) HPO42−

• (d) NH4+

• (e) H2O

• (f) NH3

Background

Topic: Conjugate Acid-Base Pairs

This question tests your ability to identify conjugate bases formed when acids lose a proton.

Key Terms and Formula:

• Conjugate base: Formed when an acid loses H+

• General formula: Acid − H+ → Conjugate base

Step-by-Step Guidance

1. For each acid, remove one H+ to get the conjugate base.

2. Write the resulting formula and adjust the charge accordingly.

3. Repeat for each given acid.

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Q15.43. Give the formula for the conjugate acid of each of the following Brønsted–Lowry bases:

• (a) SO32−

• (b) H2O

• (c) CH3NH2

• (d) OH−

• (e) HCO3−

• (f) H−

Background

Topic: Conjugate Acid-Base Pairs

This question tests your ability to identify conjugate acids formed when bases gain a proton.

Key Terms and Formula:

• Conjugate acid: Formed when a base gains H+

• General formula: Base + H+ → Conjugate acid

Step-by-Step Guidance

1. For each base, add one H+ to get the conjugate acid.

2. Write the resulting formula and adjust the charge accordingly.

3. Repeat for each given base.

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Q15.44. For each of the following reactions, identify the Brønsted–Lowry acids and bases and the conjugate acid-base pairs:

• (a) CH3CO2H(aq) + NH3(aq) → NH4+(aq) + CH3CO2−(aq)

• (b) CO32−(aq) + H3O+(aq) → H2O(l) + HCO3−(aq)

• (c) HSO3−(aq) + H2O(l) → H3O+(aq) + SO32−(aq)

• (d) HSO3−(aq) + H2O(l) → H2SO3(aq) + OH−(aq)

Background

Topic: Brønsted–Lowry Acid-Base Reactions

This question tests your ability to identify acids, bases, and their conjugate pairs in chemical reactions.

Key Terms:

• Brønsted–Lowry acid: Proton donor

• Brønsted–Lowry base: Proton acceptor

• Conjugate acid-base pair: Related by gain/loss of H+

Step-by-Step Guidance

1. For each reaction, identify which species donates a proton (acid) and which accepts it (base).

2. Determine the conjugate acid and conjugate base formed after the proton transfer.

3. Write out the pairs for each reaction.

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Q15.50. For each of the following solutions, calculate [OH−] from [H3O+], or [H3O+] from [OH−]. Classify each solution as acidic, basic, or neutral.

• (a) [H3O+] = 3.4 × 10−9 M

• (b) [OH−] = 0.010 M

• (c) [OH−] = 1.0 × 10−2 M

• (d) [H3O+] = 1.0 × 10−7 M

• (e) [H3O+] = 8.6 × 10−5 M

Background

Topic: Dissociation of Water, pH

This question tests your ability to use the relationship between hydronium and hydroxide ion concentrations and classify solutions.

Key Formula:

• Acidic:

• Basic:

• Neutral:

Step-by-Step Guidance

1. For each solution, use the formula to find the unknown concentration.

2. Compare the calculated values to determine if the solution is acidic, basic, or neutral.

3. Set up the calculation for each part, but stop before computing the final value.

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