Acidity, bascity and

• what are the best leaving groups?

  Ones that can be easily stabilise negative charge
• What are more stable anion?

  consider the conjugate base stability
• What is a bronsted lowery acid?

  species with the tendency to lose a proton
• what is a bronsted base?


  a species with a tendency to group
• what happens when pH above pKa?

  fully dissocaited
• What happens when pH is below pKa?

  is undissociated
• what does a pKa mean?

  the strength of an acid depends on the stability of the conjugate base of that acid
• what does the lower the pka mean?

  the better the leaving group
• what factors are involved in the relative stability of anions?

  • electronegative elements
  • delocalisation of negative charge
  • strength of the A-H bond
• How do electronegative elements effect relative stability of anions?

  As we increase the electronegativity of the atom upon which the negative charge sits, we increase the stabilisation of the anion
• How does delocalisation of negative charge effect stability of anions?

  The more resonance structure of the anion we can draw, the greater the stability of the anion
• How does strength of the A-H bond affect relative stability of anions?

  the weaker tha A-H bond the stronger the acid
• what does an increased electronegativity lead to?

  decreased pKa therefore an increased anion stability
• what does an increased delocalisation of charge mean?

  decreased stability and therefore an increased anion stability therefore better leaving group
• what does an decreased bond strength (A-H) mean?

  decreased pKa, increased acidity therefore better leaving group
• why are carbon acids weaker than oxygen acids?

  carbon is less electronegative than oxygen
• how to increase the strength of a carbon acid?

  Resonance
• how can hybridisation affect pKa?

  s-orbitals are held closer to the nucleus than p-orbitals. The electrons in them are lower in energy and therefore more stable. So the greater S character it has the more stable. Alkynes are most acidic