Final answer:
A solution of 0.1 M (NH4)2SO4 will be acidic due to the presence of the ammonium ion (NH4+), which is the conjugate acid of a weak base and can donate hydrogen ions to the solution.
Step-by-step explanation:
Acidity or Basicity of (NH4)2SO4 Solution
When assessing whether a solution is acidic, basic, or neutral, it's crucial to examine the properties of both the cation and anion that compose the salt. Ammonium sulfate, (NH4)2SO4, consists of ammonium ions (NH4+) and sulfate ions (SO42-). The ammonium ion is the conjugate acid of ammonia, a weak base, which means it can donate a hydrogen ion (H+) to water, forming NH3 (aq) and H3O+ (aq). This reaction indicates that ammonium ions make the solution acidic.
On the other hand, the sulfate anion is the conjugate base of sulfuric acid, which is a strong acid. Since it is the conjugate base of a strong acid, it does not significantly increase the basicity of the solution. Therefore, when (NH4)2SO4 dissolves in water, the effect of the weakly acidic ammonium ion predominates, making the overall solution acidic.