Give two examples of bases which are not alkali.

Base: these are ionic substances that when dissolved in water produce negative hydroxide $\left({\mathrm{OH}}^{-}\right)$ions.

1. Reacts with acids to form salts, and promotes certain chemical reactions (base catalysis).
2. Some bases such as Sodium hydroxide $\left(\mathrm{NaOH}\right)$ and Potassium hydroxide $\left(\mathrm{KOH}\right)$are also called alkali because these bases are soluble in water.
3. A base is a chemical species that donates electrons, accepts protons, or releases hydroxide $\left({\mathrm{OH}}^{-}\right)$ions in an aqueous solution.

Examples of bases that are not alkali:

• Copper hydroxide $\left[\mathrm{Cu}{\left(\mathrm{OH}\right)}_2\right]$
• Zinc hydroxide $\left[\mathrm{Zn}{\left(\mathrm{OH}\right)}_2\right]$
• Silver hydroxide $\left[\mathrm{Ag}{\left(\mathrm{OH}\right)}_2\right]$