The pH of an aqueous solution of FeCl_3 will be :

Question

Accepted Answer

The pH of an aqueous solution of FeCl₃ will be less than 7. Here is a detailed explanation supporting why Option 1 is correct and why the other options are incorrect:

1. **Explanation for Option 1 (Correct Answer: less than 7):**
   - FeCl₃, or iron(III) chloride, is a salt formed from the reaction of a strong acid (HCl) and a weak base (Fe(OH)₃). When FeCl₃ is dissolved in water, it undergoes hydrolysis. The Fe³⁺ ions react with water to form Fe(OH)₃ and release H⁺ ions into the solution:
     $$
     \text{Fe}^{3+} + 3\text{H}_2\text{O} \rightarrow \text{Fe(OH)}_3 + 3\text{H}^+
     $$
   - The release of H⁺ ions results in an increase in the concentration of hydrogen ions in the solution, making it acidic. Therefore, the pH of the solution will be less than 7.

2. **Explanation for Option 2 (Incorrect: 7):**
   - A pH of 7 indicates a neutral solution, which occurs when the concentrations of H⁺ and OH⁻ ions are equal. Since FeCl₃ hydrolyzes to produce additional H⁺ ions, the solution becomes acidic, not neutral. Therefore, the pH cannot be 7.

3. **Explanation for Option 3 (Incorrect: more than 7):**
   - A pH greater than 7 indicates a basic or alkaline solution. As explained, the hydrolysis of FeCl₃ results in the production of H⁺ ions, which makes the solution acidic. Therefore, the pH cannot be more than 7.

4. **Explanation for Option 4 (Incorrect: more than 14):**
   - A pH greater than 14 is not typically observed in aqueous solutions and would indicate an extremely basic solution. Given that FeCl₃ increases the concentration of H⁺ ions, the solution is acidic, not basic. Thus, the pH cannot be more than 14.

In conclusion, the hydrolysis of FeCl₃ in water leads to an acidic solution with a pH less than 7, making Option 1 the correct choice.