What is different about neutralization reactions that produce a neutral solution at the equivalence point and those that produce acidic or basic solution?
I think it is the concentration of the reactants?
No, its whether the anion, the cation, neither cation nor anion, or both cation and anion, hydrolyze.
When an acid is neutralized with a base, it forms a salt and water at the equivalence point. For example,
HCl + NaOH ==> NaCl + H2O
Since neither the Na^+ nor the Cl^- are hydrolyzed the solution is neutral.
But if you have acetic acid (CH3COOH) neutralized with NaOH it is
CH3COOH + NaOH ==> CH3OONa + H2O.
The Na^+ is not hydrolyzed but the acetate ion is as follows:
CH3COO^- + HOH ==> CH3COOH + OH^- and since the OH^- is freed it is basic.
For NH3 + HCl ==> NH4Cl, the Cl- is not hydrolyzed but the NH4^++ is as follows:
NH4^+ + H2O ==> NH3 + H3O^+ and this solution is acidic because of the freed hydronium ion.
For a weak acid + weak base such as
acetic acid + ammonia you have
CH3COOH + NH3 ==> CH3COONH4 and both are hydrolyzed with the total equation being the sum of the two respective ones above. In this case the Ka for acetic acid is the same as Kb for NH3 so the solution is neutral; however, it will be acidic if Ka is larger than Kb or basic if Kb is greater than Ka.
Hope this helps.
Oh, such a big help! Thank you!
You are correct that the concentration of reactants can play a role in determining the nature of the solution produced during a neutralization reaction. However, it is not the only factor to consider.
In a neutralization reaction, an acid and a base react to form a salt and water. The equivalence point of a neutralization reaction is the point at which stoichiometrically equivalent amounts of acid and base have reacted. At this point, the solution should ideally be neutral, with a pH of 7.
If the concentration of the acid and base reactants are equal, then the resulting solution at the equivalence point will be neutral. This is because the acid and base will completely neutralize each other, resulting in the formation of water and a salt. The concentration of the reactants influences the pH of the solution, as the more concentrated the acid or base, the more acidic or basic the solution will be respectively.
However, it is important to note that other factors can also influence the nature of the solution at the equivalence point. These factors include the strength of the acid and base, as well as their relative equilibrium constants. Strong acids and bases will completely dissociate in water, resulting in a more acidic or basic solution at the equivalence point, regardless of their concentrations. Weak acids and bases, on the other hand, may not fully dissociate, leading to a solution that is slightly acidic or basic even at the equivalence point.
Therefore, while concentration can certainly play a role in determining the pH of a neutralization reaction, it is crucial to consider other factors such as the strength of the acid and base before making a conclusion about the nature of the solution produced.