Metal oxide + acid `to` X+water, X is

Options

A. metal
B. acid
C. base
D. salt

Explanation

To solve the question, "Metal oxide + acid → X + water, what is X?", we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
- We have a metal oxide and an acid as the reactants. Metal oxides are generally basic in nature.

2. **Understand the Reaction Type**:
- The reaction between a metal oxide and an acid is a type of neutralization reaction. In this reaction, the base (metal oxide) reacts with the acid to produce a salt and water.

3. **Write the General Reaction**:
- The general form of the reaction can be written as:
\[ \text{Metal Oxide} + \text{Acid} \rightarrow \text{Salt} + \text{Water} \]

4. **Determine the Products**:
- From the neutralization reaction, we know that the products will be a salt (which is formed from the metal in the oxide and the anion from the acid) and water.

5. **Identify X**:
- In the equation provided, X represents the salt formed in the reaction. Therefore, X is the metal salt produced when the metal oxide reacts with the acid.

6. **Example for Clarity**:
- For instance, if we take zinc oxide (ZnO) reacting with hydrochloric acid (HCl), the products will be zinc chloride (ZnCl2) and water (H2O). Here, ZnCl2 is the salt formed, which confirms that X is indeed the metal salt.

### Conclusion:
- Therefore, in the reaction "Metal oxide + acid → X + water", X is the **metal salt** produced from the reaction.

---