Proton transfer reactions - strong & weak acids Flashcards
Strong acid definition
An acid that dissociates completely
What is the position of equilibrium for a strong acid?
Equilibrium lies far to the right - irreversible reaction
What conjugate base does a strong acid have?
a weak conjugate base
What are the strong acids?
HCl
HBr
HI
HNO3
H2SO4
HClO4
Dissociation of a strong acid formula
HA → H+ + A-
How do you find the pH of a strong acid?
Use [strong acid] to calculate pH
Is the conjugate base for a strong acid stronger or weaker than water and why?
Conjugate base is weaker than water because the water molecules win the competition for the H+ ions
Weak acid definition
An acid that partially dissoicates in aqueous solutions
What is the position of equilibrium for a weak acid?
Far to the left
Dissociation of a weak acid formula
HA (aq) + H2O ⇌ H3O+ (aq) + A- (aq)
How do you find the pH of a weak acid?
Use Ka to find [H+]
What conjugate base does a weak acid have?
Strong conjugate base
Is a weak acid’s conjugate base stronger or weaker than water and why?
Much stronger than water - water is not very successful in pulling off the H+ ions
Strong base definition
A base that completely dissociates in aqueous solutions
Where is the position of equilibrium for the dissoication of a strong base?
Far to the right - irreversible reaction
Dissociation of a strong base formula
BOH → OH- + B+
What are the strong bases?
LiOH
NaOH
KOH
RbOH
CsOH
Sr(OH)2
Ba(OH)2
Ca(OH)2 (only slightly soluble)
Weak base definition
A base that partially dissociates in aqueous solutions
Where is the position of equilibrium for a weak base
left
Is the concentration of OH- high or low for a weak base?
low
How can strong as weak acids be distinguished?
pH value
electrical conductivity
reactivity
Do strong acids have greater or weaker electrical conductivity and why?
A strong acid conducts electricity better as it has a higher concentration of H+.
How can electrical conductivity be measured?
Using a conductivity meter (connected to an electrode)
Are strong acids more or less reactive than weak acids and why?
More reactive as they have a higher concentration of H+. This means more H2 gas is produced in a shorter time
What would you expect to see in a reaction of a strong acid?
vigourous reaction, larger enthalpy changes, more gas produced
