Flashcards in 8.3 Strong And Weak Acids And Bases Deck (16)
What happens when an acid reacts with water?
It dissociates or ionises.
How can the reaction of acid with water be written?
HA (aq) + H2O (l) H3O+ (aq) + A- (aq)
HA (aq) H+ (aq) + A- (aq)
It can be shown with or without water, both representations are correct.
What is a strong acid?
One that dissociates completely in aqueous solution. It is a good proton donor and has a weak conjugate base.
Where does the position of equilibrium lie for the dislocation of an acid?
A long way to the right, there is very little tendency for the conjugate base to pick up a proton to re form the acid.
What is an example of a strong acid dissociating?
HCl (aq) ------> H+ (aq) + Cl- (aq)
What is a weak acid?
One that dissociates partially aqueous solution.
What is an example of a weak acid dissociating?
CH3COOH (aq) -----> CH3COO- (aq) + H+ (aq)
What happens the stronger the acid?
It dissociates more and the weaker its conjugate base.
What is a strong base?
Strong bases are group 1 hydroxides and ionise completely in aqueous solution.
What is an example of a strong base dissociating in water?
NaOH (aq) ----> Na+ (aq) + OH- (aq)
What happens when a weak base reacts with water?
It accepts a proton from the water and ionises according to the equation:
B (aq) + H2O (l) BH+ (aq) + OH- (aq)
What happens the stronger the base?
The stronger the base the better it is at accepting a proton and the weaker its conjugate acid.
What are example of weak bases?
Amines RNH2 R2NH R3N
What is important when distinguishing experimentally between solution of strong and weak acids?
You must compare solutions of equal concentrations.
How can you distinguish between strong acids and weak acids?
Strong acids conduct electricity bettie than solutions of weak acids.
Strong acids dissociate more therefore there is a higher concentration of (H+) ions in solution,
Strong acids have a lower pH than weak acids.
Strong acids react more violently with metal or carbonates - more rapid fizzing.