Which of the following statements is not correct?

Options

A. All metal carbonates react with acid to give a salt, water and carbon dioxide.
B. All metal oxides react with water to give salt and acid.
C. Some metals react with acids to give salt and hydrogen
D. Some non-metal oxides react with water to form an acid.

Explanation

To determine which statement is not correct among the given options regarding acids, bases, and salts, we will analyze each statement step by step.

### Step 1: Analyze the First Statement
**Statement:** All metal carbonates react with acid to give a salt, water, and carbon dioxide.

**Analysis:**
- When a metal carbonate (like sodium carbonate, Na2CO3) reacts with an acid (like hydrochloric acid, HCl), it produces a salt (sodium chloride, NaCl), water (H2O), and carbon dioxide (CO2).
- Example reaction:
\[ \text{Na}_2\text{CO}_3 + 2\text{HCl} \rightarrow 2\text{NaCl} + \text{H}_2\text{O} + \text{CO}_2 \]
- This statement is correct.

### Step 2: Analyze the Second Statement
**Statement:** All metal oxides react with water to give salt and acid.

**Analysis:**
- When a metal oxide (like sodium oxide, Na2O) reacts with water (H2O), it produces a base (sodium hydroxide, NaOH), not a salt and acid.
- Example reaction:
\[ \text{Na}_2\text{O} + \text{H}_2\text{O} \rightarrow 2\text{NaOH} \]
- This statement is incorrect.

### Step 3: Analyze the Third Statement
**Statement:** Some metals react with acid to give salt and hydrogen.

**Analysis:**
- Some metals (like sodium) react with acids (like sulfuric acid, H2SO4) to produce a salt (sodium sulfate, Na2SO4) and hydrogen gas (H2).
- Example reaction:
\[ \text{2Na} + \text{H}_2\text{SO}_4 \rightarrow \text{Na}_2\text{SO}_4 + \text{H}_2 \]
- This statement is correct.

### Step 4: Analyze the Fourth Statement
**Statement:** Some non-metal oxides react with water to form an acid.

**Analysis:**
- Non-metal oxides (like sulfur dioxide, SO2) can react with water to form an acid (sulfurous acid, H2SO3).
- Example reaction:
\[ \text{SO}_2 + \text{H}_2\text{O} \rightarrow \text{H}_2\text{SO}_3 \]
- This statement is correct.

### Conclusion
After analyzing all the statements, we find that the second statement is not correct.

**Final Answer:** The statement that is not correct is: "All metal oxides react with water to give salt and acid."

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