What is an acid according to Arrhenius theory?
According to the Arrhenius theory, an acid is a substance that increases the concentration of hydronium ions (H₃O⁺) when dissolved in water.
- What is a base according to Arrhenius theory?
According to the Arrhenius theory, a base is a substance that increases the concentration of hydroxide ions (OH⁻) when dissolved in water.
- What is the Bronsted-Lowry theory of acids and bases?
The Bronsted-Lowry theory states that an acid is a proton (H⁺) donor, and a base is a proton (H⁺) acceptor.
- How does the Lewis theory define acids and bases?
The Lewis theory defines an acid as a species that accepts an electron pair, and a base as a species that donates an electron pair.
- What is a conjugate acid-base pair?
A conjugate acid-base pair consists of two species that differ only by the presence or absence of a proton. A conjugate acid is formed by protonation of a base, while a conjugate base is formed by deprotonation of an acid.
- What is an example of a conjugate acid-base pair?
An example of a conjugate acid-base pair is NH₄⁺ (ammonium) and NH₃ (ammonia). NH₄⁺ is the conjugate acid of NH₃, and NH₃ is the conjugate base of NH₄⁺.
- What is the pH scale?
The pH scale is a logarithmic scale that measures the acidity or basicity of a solution. It is defined as the negative logarithm (base 10) of the concentration of hydronium ions (H₃O⁺). A pH of 7 is neutral, values less than 7 are acidic, and values greater than 7 are basic.
- What is an amphoteric substance?
An amphoteric substance is a substance that can act as both an acid and a base. For example, water can donate a proton (acting as an acid) or accept a proton (acting as a base).
- How is the pOH of a solution related to its pH?
The pOH of a solution is defined as the negative logarithm (base 10) of the concentration of hydroxide ions (OH⁻). For any aqueous solution at 25°C, the sum of the pH and the pOH is always 14.
- What is a strong acid?
A strong acid is an acid that completely ionizes in aqueous solution, releasing all its protons into the solution. Examples include hydrochloric acid (HCl), nitric acid (HNO₃), and sulfuric acid (H₂SO₄).
- What is a strong base?
A strong base is a base that completely dissociates in water to produce hydroxide ions (OH⁻). Examples include sodium hydroxide (NaOH) and potassium hydroxide (KOH).
- What is a weak acid?
A weak acid is an acid that only partially ionizes in aqueous solution, releasing only some of its protons into the solution. An example is acetic acid (CH₃COOH).
- What is a weak base?
A weak base is a base that only partially dissociates in water to produce hydroxide ions (OH⁻). An example is ammonia (NH₃).
- What is Kw, the ion product of water?
Kw, the ion product of water, is the product of the concentrations of hydronium ions (H₃O⁺) and hydroxide ions (OH⁻) in pure water. At 25°C, Kw is 1.0 x 10⁻¹⁴.
- What is the autoionization of water?
The autoionization of water is the process by which water undergoes a self-ionization reaction, producing hydronium (H₃O⁺) and hydroxide (OH⁻) ions: 2H₂O ⇌ H₃O⁺ + OH⁻.
- What are titrations used for in the context of acids and bases?
Titrations are used to determine the concentration of an unknown acid or base by neutralizing it with a solution of a base or acid of known concentration.
- What is an indicator in acid-base titrations?
An indicator is a compound that changes color at or near the equivalence point in an acid-base titration. The color change signals that the correct amount of acid or base has been added to neutralize the solution.
- What is a buffer solution?
A buffer solution is a solution that resists changes in pH when small amounts of acid or base are added or when the solution is diluted. Buffers are typically made from a weak acid and its conjugate base, or a weak base and its conjugate acid.
- What is the Henderson-Hasselbalch equation?
The Henderson-Hasselbalch equation is a simplified expression of the acidity constant of a weak acid or base. It is pH = pKa + log([A⁻]/[HA]), where [A⁻] is the concentration of the base and [HA] is the concentration of the acid.
- What is the role of water in acid-base reactions?
Water can act as an acid or a base in acid-base reactions. In the presence of a base, water acts as an acid by donating a proton to form a hydroxide ion. In the presence of an acid, water acts as a base by accepting a proton to form a hydronium ion.
