Question

Will phthalimide dissolve in aqueous sodium bicarbonate?

Short answer

Why or why not?

Step-by-step solution

Identifying the acidic and basic components

In this exercise, we first need to identify the acidic and basic components in both compounds. Phthalimide contains a nitrogen atom with a lone pair of electrons, commonly referred to as a weak base. Sodium bicarbonate, on the other hand, is composed of a sodium cation and bicarbonate anion (HCO₃¯). The bicarbonate ion can act as an acidic or basic species, depending on its environment.

Evaluate the possibility of an acid-base reaction

Next, we need to evaluate if an acid-base reaction can take place between the two compounds. An acid-base reaction requires the transfer of a proton (H⁺) from an acid to a base. Since phthalimide is a weak base and the bicarbonate ion can act as an acid, an acid-base reaction could potentially occur between these two species. However, the reaction will only proceed if the product produced is more stable than the reactants.

Predict the products of the reaction

If an acid-base reaction occurs, we can predict the products formed. The bicarbonate ion will donate a proton (H⁺) to the nitrogen atom in phthalimide: Phthalimide + HCO₃¯ → Phthalimidium ion + CO₂ + H₂O The phthalimidium ion would be the conjugate acid of phthalimide, and the reaction would also produce carbon dioxide gas and water as additional products.

Assess the stability of the products

Now, we need to assess the stability of the products to determine if the reaction is favorable. The phthalimidium ion has a positive charge on the nitrogen atom, making it less stable than the initial reactants. Additionally, the formation of carbon dioxide gas could contribute to the reaction proceeding, as gases are often considered driving forces in reactions. However, phthalimide's resonance stabilization and its relatively low basicity means that the reaction, if occurring, will be quite slow and ineffective. Thus, phthalimide will not dissolve appreciably in aqueous sodium bicarbonate.

Conclusion

Phthalimide, being a weak base, is unlikely to dissolve in aqueous sodium bicarbonate as the products of the possible acid-base reaction are not significantly more stable than the reactants.