10.3 Strong and Weak Bases
LO: I understand the difference
between strong and weak bases.
10.3.1 Strong Bases
A base is a substance that neutralises an acid.
A strong base is a substance that is fully ionised
to give hydroxide ions when dissolved in water.
e.g. sodium hydroxide:
NaOH(s) + water
LO:
Na+(aq) + OH-(aq)
I understand the difference between strong and weak bases.
10.3.2 Weak Bases
A weak base is a substance that is only partially
ionised to give hydroxide ions when dissolved in
water.
e.g. ammonia solution:
NH3(aq) + H2O(l)
NH4+(aq) + OH-(aq)
99.6% of the ammonia remains as covalent molecules .
The equilibrium lies very much to the left .
LO:
I understand the difference between strong and weak bases.
10.3.3 Comparing Strong and Weak Bases
Reactions of Bases
In comparison to a strong base, a weak base:
•Has a lower pH
•Has a lower conductivity
•Reacts at a slower rate.
The stoichiometry is identical for equimolar strong
and weak bases.
LO: I understand the difference between strong and weak bases.