WEAK ACIDS/ BASES

• STRONG ACIDS/ BASES?

  completely dissociate into ions in aqueous solution
• WEAK ACIDS/ BASES?

  only slightly ionised in aqueous solution
• EXAMPLES OF STRONG ACIDS/ BASES?

  • HCl
  • HNO3
  • H2SO4
  • NaOH
  • KOH
  • Ba(OH)2
• EXAMPLES OF WEAK ACIDS/ BASES?

  • NH3
  • carboxylic acids
• EQUATION FOR DISSOCIATION OF WEAK ACIDS?

  HA (aq) ⇋ H+ (aq) + A- (aq)
• EQUATION FOR ACID DISSOCIATION CONSTANT?

  Ka = [H+][A-]/[HA]
• EQUATION FOR ACID DISSOCIATION CONSTANT IN A SOLUTION OF WEAK ACID AND WATER WITH NOTHING ELSE?

  Ka = [H+]^2/ [HA]
• ASSUMPTIONS?

  • [H+] = [A-]
  • [HA]eqm = [HA]initial
• IF Ka IS BIGGER WHAT DOES IT MEAN?

  stronger acid
• EQUATION FOR pKa?

  pKa = -logKa

  Ka = 10^-pKa
• IF pKa IS BIGGER WHAT DOES IT MEAN?

  weaker acid