‘Which of the following is a STRONG base? NO3 b. CH3OH KOH d_ NH3 Cl’
The Correct Answer and Explanation is:
The correct answer is KOH.
A strong base is a substance that completely dissociates in water to release hydroxide ions (OH⁻). In the given options:
- NO3⁻ (Nitrate ion): This is an anion, not a base itself. It’s typically part of a salt (e.g., NaNO3), and does not directly accept protons (H⁺), which is the behavior of bases.
- CH3OH (Methanol): Methanol is an alcohol and is weakly basic at best. It can accept a proton, but it does not dissociate significantly in water to produce OH⁻ ions, so it is not considered a strong base.
- KOH (Potassium hydroxide): This is a strong base. When KOH is dissolved in water, it dissociates completely into potassium ions (K⁺) and hydroxide ions (OH⁻). The hydroxide ion (OH⁻) is what gives KOH its strong basic properties. This complete dissociation in water is the key characteristic of strong bases.
- NH3 (Ammonia): Ammonia is a weak base. It can accept a proton to form ammonium (NH4⁺), but it does not dissociate completely in water to release OH⁻ ions. Its basicity is weaker compared to KOH.
Explanation:
KOH dissociates in water as follows:
KOH(aq)→K+(aq)+OH−(aq)KOH (aq) \rightarrow K^+ (aq) + OH^- (aq)KOH(aq)→K+(aq)+OH−(aq)
The presence of OH⁻ ions in solution makes KOH a strong base, capable of increasing the pH significantly when dissolved in water. This is in contrast to weak bases like NH3, which only partially dissociate and do not produce as many hydroxide ions in solution.
In summary, KOH is the strongest base among the given options because it completely dissociates in water, providing a high concentration of OH⁻ ions.
