If ammonia is dissolved in water, pH of the solution

Options

A. increase
B. Dereases
C. May increase or decrease
D. None of these

Answer

To determine the pH of a solution when ammonia is dissolved in water, we can follow these steps:

### Step 1: Understand the Dissolution of Ammonia
When ammonia (NH₃) is dissolved in water, it undergoes a reaction to form ammonium ions (NH₄⁺) and hydroxide ions (OH⁻). The reaction can be represented as:
\[ \text{NH}_3 + \text{H}_2\text{O} \rightleftharpoons \text{NH}_4^+ + \text{OH}^- \]

### Step 2: Identify the Nature of the Solution
The formation of hydroxide ions (OH⁻) indicates that the solution becomes basic (alkaline). This is because the increase in OH⁻ concentration leads to a decrease in the concentration of hydrogen ions (H⁺).

### Step 3: Relate pH to OH⁻ Concentration
The pH scale ranges from 0 to 14, where:
- A pH of 7 is neutral (equal concentrations of H⁺ and OH⁻).
- A pH less than 7 indicates an acidic solution (higher concentration of H⁺).
- A pH greater than 7 indicates a basic solution (higher concentration of OH⁻).

Since the dissolution of ammonia increases the concentration of OH⁻, the pH of the solution will be greater than 7.

### Step 4: Conclusion on pH
Given that the solution becomes basic due to the increase in OH⁻ ions, we can conclude that the pH of the ammonia solution will be above 7, indicating that it is in the basic range.

### Final Answer
The pH of the solution when ammonia is dissolved in water will increase and will be in the range of 7 to 14.

---