Metals generally form

Options

A. basic oxides
B. acidic oxides
C. neutral oxides
D. none

Answer

**Step-by-Step Solution:**

1. **Understanding Metal Oxides:**
Metals generally form oxides when they react with oxygen. These metal oxides can be classified based on their chemical properties.

2. **Basic Oxides Formation:**
The primary type of oxide formed by metals is known as basic oxides. When metal oxides are dissolved in water, they react to form hydroxides, which are basic in nature.

3. **Reaction with Water:**
For example, when a metal oxide like sodium oxide (Na2O) is added to water, it reacts to form sodium hydroxide (NaOH):
\[ \text{Na}_2\text{O} + \text{H}_2\text{O} \rightarrow 2 \text{NaOH} \]
This reaction increases the concentration of hydroxide ions (OH⁻) in the solution.

4. **Increase in pH:**
The increase in hydroxide ions leads to an increase in the pH of the solution, indicating that the solution is basic. This is a characteristic property of metal oxides.

5. **Comparison with Non-Metals:**
In contrast, non-metals typically form acidic oxides. When these oxides, such as carbon dioxide (CO2), are dissolved in water, they form acids (like carbonic acid, H2CO3):
\[ \text{CO}_2 + \text{H}_2\text{O} \rightarrow \text{H}_2\text{CO}_3 \]
This reaction increases the concentration of hydrogen ions (H⁺) in the solution, leading to a decrease in pH, indicating that the solution is acidic.

6. **Conclusion:**
Therefore, metals generally form basic oxides, which increase the pH of the solution when dissolved in water, while non-metals form acidic oxides, which decrease the pH.

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