Question

which of these is not a strong base? koh al(oh)₃ naoh ca(oh)₂

Explanation:

Strong bases are typically hydroxides of Group 1 (alkali metals) and Group 2 (alkaline earth metals) elements that dissociate completely in water. KOH (potassium hydroxide, Group 1), NaOH (sodium hydroxide, Group 1), and Ca(OH)₂ (calcium hydroxide, Group 2) are strong bases. Al(OH)₃ (aluminum hydroxide) is an amphoteric substance and a weak base as it does not dissociate completely in water.

Answer:

B. $\ce{Al(OH)_{3}}$