Acis&bases

• Arrhenius acid is a species that poduces H+ in aqueous solution
• Arrhenius base is a species that produce OH- in aqueous solution
• when arrhenius acid reacts with arrhenius base, neutralization reaction occurs
• Bronstead-Lowry acid is a species that produces H+
• Bronsted-Lowry Base is a species that accepts H+
• Lewis acid is a species that acts as an electron-pair acceptor
• Lewis base is a species that acts as an electron-pair donor
• Lewis acids are electrophiles
• Lewis bases are nucleophiles
• Relative acidity of compounds depend on the strength of bonds with H, polarity of the bond and stability of the conjugate base
• Stronger bond between H and another atom, means this molecule is less acidic
• Stronger bonds are also shorter bonds
• Polarity of the molecule increases with increasing electronegativity difference between atoms
• In oxyacids, the more O molecule has, the more acidic it is
• HF is a weak acid because F- is unstable conjugate base
• In terms of basic amino acids, lysine is less basic than arginine
• Strong acid or base completely dissociates in water forming H+ or OH-
• Acid dissociation decreases with acid concentration, but acid strength increases
• Acidity trend for hydrates is that acidity increases to the right across group and down the period
• The stronger the acid, the weaker its conjugate base
• If concentration of acid or base added to water solution is less than concentration of ions in water (10 in -7), then the actual pH will always be closer to neutral
• Ka greater than 1 indicates a strong acid
• Higher Ka, means lower pKa and stronger acid
• Strong acid + weak base forms an acidic salt
• Strong base + weak acid forms a basic salt
• Adding electron withdrawing groups to the compound increases its acidity
• Buffer is a mixture of a conjugate acid-base pair that can resist changes in pH when small volumes of strong acids or bases are added.
• Strong acids to remember are HCl, HBr, HI, H2SO4, HNO3, HClO3, HCLO4
• Strong bases to remember: NaOH, KOH, CaO, Na2O, H-, Ca(OH)2, Ba(OH)2, Sr(OH)2
• Strong acid and strong base will have equivalence point at pH of 7
• This is a titration curve

  A) equivalence point

  B) half-equivalence point

  C) pH=pKa

  D) Buffer region: pKa +/- 1 pH

  
• When determining which indicator to use for titration, choose the one with pKa closest to the pH of the titration's equivalence point
• A buffer solution needs to have equal amounts of a weak acid and its conjugate base
• Titration curve of polyprotic acid H2A shows concentration of acid and its conjugated bases

  A) 50% H2A 50% HA-

  B) 100% HA-

  C) 50% HA- 50% A2-

  D) 100% A2-

  
• Acids will turn litmus paper red
• Bases will turn litmus paper blue
• If Ka of a weak acid is greater than 10 in -7, then its conjugate base will be weaker
• If Ka of a weak acid is less than 10 in -7, then its conjugate base will be stronger
• Acid strength is determined by 4 factors that can be abbreviated as ARIO
• The more spread out or stable negative charges, the weaker would be the base