Consider a 0.71 M solution of each of the following salt dissolved in distilled water. Will the solution by basic, neutral, or acidic?
KI=
NH4NO2=
(CH3CH2)3NHNO2=
(CH3CH2)2NH2ClO4=
All of this hinges on whether the cation or anion act as acids or bases when dissolved in H2O.
For salts of strong acids and strong bases (example KI) neither is hydrolyzed and the solution should be neutral.
For salts of weak acids and weak bases (examples are #2 and #3), compare Ka for acid and Kb for base. The stronger one dictates if the solution is acid or basic. If Ka = Kb the soln will be neutral.
For the last one, it is salt of weak base and strong acid; the soln will be acid.
To determine if a solution is basic, neutral, or acidic, we need to analyze the ions produced by the salt when it dissolves in water.
First, let's examine each salt:
1. KI: When KI dissolves in water, it dissociates into K+ and I- ions. Neither of these ions affect the pH of the solution. Therefore, the solution will be neutral.
2. NH4NO2: When NH4NO2 dissolves in water, it dissociates into NH4+ and NO2- ions. NH4+ acts as an acid (donates H+ ions), while NO2- acts as a weak base (accepts H+ ions). Based on the acidity of NH4+, the solution will be slightly acidic.
3. (CH3CH2)3NHNO2: When (CH3CH2)3NHNO2 dissolves in water, it dissociates into (CH3CH2)3NH+ and NO2- ions. (CH3CH2)3NH+ acts as a weak base, accepting H+ ions. The solution will be slightly basic.
4. (CH3CH2)2NH2ClO4: When (CH3CH2)2NH2ClO4 dissolves in water, it dissociates into (CH3CH2)2NH2+ and ClO4- ions. (CH3CH2)2NH2+ also acts as a weak base, accepting H+ ions. Thus, the solution will be slightly basic.
In summary:
- KI will result in a neutral solution.
- NH4NO2, (CH3CH2)3NHNO2, and (CH3CH2)2NH2ClO4 will produce slightly acidic or basic solutions.
Please note that the degree of acidity or basicity will depend on the strength of the acids or bases involved.