Quiz 1 - Acids and Bases | Acids and Bases

The pH scale is unrelated to the dissociation of water since pH measures only the hydronium ion concentration.

An increase in the dissociation of water leads to a decrease in pH, as it indicates a higher concentration of hydroxide ions.

The pH scale inversely reflects the extent of water dissociation; an increase in water's dissociation increases pH.

Water dissociation is central to the pH scale; pH represents the negative logarithm of the hydronium ion concentration.

Hydrofluoric acid (HF), with a K_a of 6.8 x 10⁻⁴

Acetic acid (CH₃CO₂H), with a K_a of 1.8 x 10⁻⁵

Formic acid (HCOOH), with a K_a of 1.8 x 10⁻⁴

Hydrocyanic acid (HCN), with a K_a of 4.9 x 10⁻¹⁰

NH₃ forms a conjugate acid (NH₄⁺) after accepting a proton from water, which acts as its conjugate base (OH^-).

NH₃ donates a proton to form its conjugate base (NH₂^-), with water acting as the conjugate acid (H₃O⁺).

NH₃ and water do not form a conjugate acid-base pair, as they react to form NH₄⁺ and OH^- without proton transfer.

NH₃ acts as a conjugate base to water's conjugate acid, resulting in the formation of NH₂^- and H₃O⁺.

Both ionizations contribute equally to the pH, which is calculated by the average of the pK_a1 and pK_a2 values.

Only the first ionization is significant for pH calculation; the second ionization's contribution is negligible.

The second ionization dominates the pH calculation since it results in the direct production of hydroxide ions.

The pH is determined by the intermediate ion H₂A^-, which controls the overall ionization process.

A lower K_b value indicates a stronger base, as it signifies a greater ability to accept protons.

K_b value has no impact on base strength; it is determined purely by the molecular structure of the base.

A higher K_b value correlates with a stronger base, reflecting a greater ability to accept protons.

The K_b value inversely correlates with base strength; bases with similar molecular structures have equal strengths.

A substance that increases the concentration of hydroxide ions in solution.

A substance that donates protons (H⁺) to another substance.

A substance that accepts protons (H⁺) from another substance.

A substance that forms a salt when reacting with a base.

5

9

7

4

It dissociates in one step, releasing two protons simultaneously.

It has the same ionization constant (K_a​) for both proton releases.

It can only be neutralized by a single base molecule.

It dissociates in two steps, releasing one proton at a time.

K_b = $\frac{\left[{\mathrm{NH}}_3\right]\left[{\mathrm{H}}^{+}\right]}{\left[{{\mathrm{NH}}_4}^{+}\right]}$

K_b = $\frac{\left[{\mathrm{NH}}_3\right]\left[{\mathrm{H}}_2\mathrm{O}\right]}{\left[{{\mathrm{NH}}_4}^{+}\right]\left[{\mathrm{HO}}^{-}\right]}$

K_b = $\frac{\left[{{\mathrm{NH}}_4}^{+}\right]\left[\right[{\mathrm{HO}}^{-}]}{\left[{\mathrm{NH}}_3\right]}$

K_b = $\frac{\left[{\mathrm{HO}}^{-}\right]}{\left[{{\mathrm{NH}}_4}^{+}\right]}$

4.74

5.30

10.0

1.8