Which of the following bases is known to be strong?

The identification of a strong base hinges on its ability to completely dissociate in solution to produce hydroxide ions (OH⁻), which is an essential characteristic for classifying a substance as a strong base. Calcium hydroxide, represented as Ca(OH)₂, meets this criterion because it dissociates completely in water into calcium ions (Ca²⁺) and hydroxide ions (OH⁻). Therefore, when Ca(OH)₂ is dissolved in water, it significantly increases the concentration of hydroxide ions, resulting in a highly alkaline solution.

In contrast, the other substances listed do not behave as strong bases. Potassium chloride (KCl) is a neutral salt formed from a strong acid and a strong base, yielding no hydroxide ions in solution. Carbonic acid (H₂CO₃) is a weak acid and will not generate hydroxide ions, reducing the pH of the solution. Sodium bicarbonate (NaHCO₃) is a weak base that only partially dissociates in solution, hence it does not qualify as a strong base.

In summary, Ca(OH)₂ stands out among the listed options as it completely dissociates in aqueous solutions, making it a clear example of a strong