When a metal X is added to dilute HCl solution, there is no evolution of gas. The metal X is

Options

A. K
B. Na
C. Ag
D. Zn

Explanation

To solve the question, "When a metal X is added to dilute HCl solution, there is no evolution of gas. The metal X is," we will follow these steps:

### Step 1: Understand the Reaction
When a metal reacts with dilute hydrochloric acid (HCl), it can either evolve hydrogen gas or not, depending on the metal's reactivity compared to hydrogen.

### Step 2: Identify the Metals
We are given four metals to consider:
- A: Potassium (K)
- B: Sodium (Na)
- C: Silver (Ag)
- D: Zinc (Zn)

### Step 3: Refer to the Reactivity Series
The reactivity series ranks metals based on their ability to displace hydrogen from acids. Metals above hydrogen in the reactivity series will react with dilute HCl to produce hydrogen gas, while metals below hydrogen will not.

### Step 4: Analyze Each Metal
1. **Potassium (K)**: Highly reactive, will react with dilute HCl and produce hydrogen gas.
2. **Sodium (Na)**: Also highly reactive, will react with dilute HCl and produce hydrogen gas.
3. **Silver (Ag)**: Less reactive than hydrogen, will not react with dilute HCl, hence no gas will be evolved.
4. **Zinc (Zn)**: Reactive enough to displace hydrogen from HCl, will produce hydrogen gas.

### Step 5: Conclusion
Since we are looking for a metal that does not evolve gas when added to dilute HCl, the only metal from the options that fits this criterion is **Silver (Ag)**.

### Final Answer
The metal X is **Silver (Ag)**.

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