Is Calcium Hydroxide a weak alkali?

Calcium hydroxide (Ca(OH)2), commonly known as slaked lime or hydrated lime, is classified as a strong base rather than a weak alkali. It is a strong base because it dissociates almost completely in water, releasing hydroxide ions (OH-) that can react with acids to form water and a corresponding salt.

When calcium hydroxide dissolves in water, it undergoes the following dissociation reaction:

Ca(OH)2(s) + 2H2O(l) -> Ca2+(aq) + 2OH-(aq)

The release of hydroxide ions in water makes calcium hydroxide strongly alkaline. Its aqueous solution has a high pH and exhibits typical properties of a strong base, such as the ability to neutralize acids and form salts.

It's worth noting that the term "alkali" is often used to refer specifically to the soluble hydroxides of Group 1 elements (e.g., sodium hydroxide, potassium hydroxide). While calcium hydroxide is not a Group 1 hydroxide, it shares similar properties with them and is often considered a strong base rather than an alkali.