Question

202(c) Give two examples of weak bases.

Answer 1

Part 1: Weak Bases

• The bases that do not dissociate completely into their ions when dissolved in an aqueous solution are called weak bases.
• When weak bases are dissolved in a solution, a part of them dissociates into hydroxide ions and some parts remain undissociated in the solution.

Part 2: Example of Weak Base:

1. Ammonia $\left({\mathrm{NH}}_3\right)$ is a weak base as it does not dissociate completely in water. When dissolved in water, it will form an Ammonium cation $\left({\mathrm{NH}}_4^{+}\right)$ and the hydroxide anion $\left({\mathrm{OH}}^{-}\right)$.
2. Aluminum hydroxide $\left[\mathrm{Al}{\left(\mathrm{OH}\right)}_3\right]$ is weak as it does not dissociate completely in water. When dissolved in water, it will form Aluminium ions and hydroxide ions which are in equilibrium with aluminum hydroxide.