Sr(OH)₂, or strontium hydroxide, is classified as a strong base. This is because it fully dissociates in water to produce strontium ions (Sr²⁺) and hydroxide ions (OH⁻). When strontium hydroxide is dissolved in water, it increases the concentration of hydroxide ions significantly, leading to a high pH solution, which is characteristic of strong bases.
To elaborate, strong bases are substances that dissociate completely in solution, unlike weak bases, which only partially dissociate. Strontium hydroxide falls under the category of alkali metal and alkaline earth metal hydroxides, which are generally strong bases. Thus, in the context of acid-base chemistry, Sr(OH)₂ behaves very much like other strong bases such as NaOH or KOH.