Acidity, bascity and

Created by

Isabelle

Cards (18)

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