Final answer:
LiOH (lithium hydroxide) is the strong base among the listed options. Strong bases completely dissociate in water, releasing hydroxide ions.
Step-by-step explanation:
The student asked which of the following is a strong base: a. LiOH b. Mg(OH)₂ c. HCl d. NH₃ e. Al(OH)₃. Among the provided options, the compound that is a strong base is LiOH (lithium hydroxide).
Strong bases are typically the hydroxides of alkali metals (such as LiOH, NaOH, KOH) and some alkaline earth metals (such as Ca(OH)₂, Sr(OH)₂, and Ba(OH)₂).
These compounds dissociate fully in water, producing hydroxide ions (OH⁻) and corresponding metal ions.
In contrast, HCl is a strong acid, not a base. NH₃ (ammonia) is a weak base because it does not contain an OH compound and does not dissociate completely in water.
Al(OH)₃ (aluminum hydroxide) and Mg(OH)₂ (magnesium hydroxide) are considered to be weak bases because they are not as fully dissociative in water as a strong base would be.