The nitrate ion is considered a strong conjugate base. True or false? Explain.
The Correct Answer and Explanation is:
False. The nitrate ion (NO₃⁻) is not considered a strong conjugate base.
To understand why, let’s first break down the concept of conjugate acids and bases. A conjugate base is the species that remains after an acid donates a proton (H⁺). The strength of a conjugate base depends on how readily it accepts a proton to form its corresponding acid. Strong acids tend to have weak conjugate bases, while weak acids tend to have stronger conjugate bases.
The nitrate ion (NO₃⁻) is the conjugate base of nitric acid (HNO₃), a strong acid. Nitric acid dissociates completely in water:
HNO3→H++NO3−HNO_3 \rightarrow H^+ + NO_3^-HNO3→H++NO3−
Because nitric acid is a strong acid, it ionizes almost completely in aqueous solution. As a result, the nitrate ion is a weak conjugate base. This means that it does not readily accept protons from water or other species to form HNO₃ again. This weak ability to re-accept a proton makes NO₃⁻ a weak base.
In contrast, a strong conjugate base would be one that has a very high affinity for protons, typically coming from a weak acid. For example, the conjugate base of ammonia (NH₃), which is a weak acid, is a much stronger base, able to readily accept a proton and form NH₄⁺.
In summary, the nitrate ion is a weak conjugate base because it comes from a strong acid (HNO₃), which means it has little tendency to accept a proton and return to its acid form. Therefore, it cannot be classified as a strong conjugate base.
