Solid calcium oxide reacts vigorously with water to form calcium hydroxide accompanied by liberation of heat. This process is called slaking of lime. Calcium hydroxide dissolves in water to form its solution called lime water. Which among the following are true about slaking of lime and the solution formed?
(i) It is an endothermic reaction.
(ii) It is exothermic reation.
(iii) The pH of the resulting solution will be more than seven.
(iv) The pH of the resulting solution will be less than seven.

Options

A. `(i) and (ii)`
B. `(ii) and (iii)`
C. `(i) and (iv)`
D. `(iii) and (iv)`

Explanation

To solve the question regarding the reaction of solid calcium oxide with water, we will analyze the statements provided and determine which are true based on our understanding of the chemical reaction and the properties of the resulting solution.

### Step-by-Step Solution:

1. **Identify the Reaction**:
- When solid calcium oxide (CaO) reacts with water (H₂O), it forms calcium hydroxide (Ca(OH)₂) and releases heat. This reaction can be represented as:
\[ \text{CaO (s)} + \text{H}_2\text{O (l)} \rightarrow \text{Ca(OH)}_2 \text{ (aq)} + \text{Heat} \]

2. **Determine the Nature of the Reaction**:
- Since heat is released during the reaction, it is classified as an **exothermic reaction**. Therefore, statement (i) "It is an endothermic reaction" is **false**, and statement (ii) "It is an exothermic reaction" is **true**.

3. **Analyze the Resulting Solution**:
- The product formed, calcium hydroxide (Ca(OH)₂), is known to be a base. When dissolved in water, it creates a solution known as lime water.

4. **Determine the pH of the Solution**:
- Bases have a pH greater than 7. Since calcium hydroxide is a basic compound, the pH of the resulting lime water will be greater than 7. Therefore, statement (iii) "The pH of the resulting solution will be more than seven" is **true**, and statement (iv) "The pH of the resulting solution will be less than seven" is **false**.

5. **Summarize the True Statements**:
- From the analysis, we conclude that:
- Statement (ii) is true: It is an exothermic reaction.
- Statement (iii) is true: The pH of the resulting solution will be more than seven.

### Final Conclusion:
The correct statements regarding slaking of lime and the solution formed are:
- (ii) It is an exothermic reaction.
- (iii) The pH of the resulting solution will be more than seven.