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Acid-Base Indicators
Acid Dissociation Constant
Acid Strength and Conjugate Base Strength
Water as an Acid and Base
pH and pOH
Ionic product of water Kw
protonation and deprotonation
Definition:
- Arrhenius Acid: Produces $ H^+ $ ions (protons) in aqueous solution. Example: $ HCl \rightarrow H^+ + Cl^- $
- Arrhenius Base: Produces $ OH^- $ ions (hydroxide ions) in aqueous solution. Example: $ NaOH \rightarrow Na^+ + OH^- $
- Brønsted-Lowry Acid: Proton ( $ H^+ $ ) donor.
- Brønsted-Lowry Base: Proton ( $ H^+ $ ) acceptor.
Strength:
- Strong Acids: Completely dissociate in water. Examples: $ HCl $ , $ HBr $ , $ HI $ , $ HNO_3 $ , $ H_2SO_4 $ , $ HClO_4 $ .
- Weak Acids: Partially dissociate in water. Example: $ CH_3COOH \rightleftharpoons CH_3COO^- + H^+ $ $ K_a = \frac{[CH_3COO^-]][H^+]]}{[CH_3COOH]]} $
- Strong Bases: Completely dissociate in water. Examples: Group 1 hydroxides (NaOH, KOH, etc.)
- Weak Bases: Partially dissociate in water. Example: $ NH_3 + H_2O \rightleftharpoons NH_4^+ + OH^- $ $ K_b = \frac{[NH_4^+]][OH^-]]}{[NH_3} $
pH and pOH:
- $ pH = -\log[H^+]] $
- $ pOH = -\log[OH^-]] $
- $ pH + pOH = 14 $ at $ 25^\circ C $
Neutralization Reactions: Reaction between an acid and a base, producing salt and water. $ HCl(aq) + NaOH(aq) \rightarrow NaCl(aq) + H_2O(l) $
Titrations: A method to determine the concentration of an unknown solution using a solution of known concentration. Titration Curves
Buffers: Solutions that resist changes in pH upon addition of small amounts of acid or base. Buffer Solutions
Related Notes:
- Equilibrium : Many acid-base reactions are equilibrium reactions. Understanding equilibrium constants ( $ K_a $ , $ K_b $ ) is crucial.
- Le Chateliers Principle: Predicts the shift in equilibrium when conditions are changed (e.g., adding acid/base).