Select the correct statements.
(i) Magnesium ribbon on heating in air catches fire and burns with white flame to form magnesium oxide.
(ii) All metals react with water to evolve hydrogen gas.
(iii) Iron reacts with cold water slowly.
(iv) Sodium metal is always kept in kerosene as it reacts vigorously with air and moisture.

Options

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

Explanation

To solve the question, we need to evaluate each statement one by one and determine if they are correct or incorrect.

### Step-by-Step Solution:

1. **Evaluate Statement (i)**:
- The statement says, "Magnesium ribbon on heating in air catches fire and burns with a white flame to form magnesium oxide."
- **Analysis**: When magnesium is heated in air, it indeed catches fire and burns with a bright white flame. The product formed is magnesium oxide (MgO).
- **Conclusion**: This statement is **correct**.

2. **Evaluate Statement (ii)**:
- The statement claims, "All metals react with water to evolve hydrogen gas."
- **Analysis**: Not all metals react with water. Only certain metals, such as sodium and potassium, react vigorously with water to produce hydrogen gas. Others, like iron and copper, do not react with water at all.
- **Conclusion**: This statement is **incorrect**.

3. **Evaluate Statement (iii)**:
- The statement states, "Iron reacts with cold water slowly."
- **Analysis**: Iron does not react with cold water. It reacts with steam (hot water) to form iron oxide and hydrogen gas. Therefore, this statement is misleading.
- **Conclusion**: This statement is **incorrect**.

4. **Evaluate Statement (iv)**:
- The statement mentions, "Sodium metal is always kept in kerosene as it reacts vigorously with air and moisture."
- **Analysis**: Sodium is indeed a highly reactive metal that reacts vigorously with both air and moisture. To prevent such reactions, sodium is stored in kerosene oil.
- **Conclusion**: This statement is **correct**.

### Final Conclusion:
The correct statements are:
- Statement (i): Correct
- Statement (ii): Incorrect
- Statement (iii): Incorrect
- Statement (iv): Correct

Thus, the correct options are **(i) and (iv)**.