Which of these metals would react vigorously with dilute hydrochloric acid?

Options

A. Magnesium
B. Potassium
C. Aluminium
D. Iron

Answer

To determine which metal reacts vigorously with dilute hydrochloric acid, we can follow these steps:

### Step 1: Understand the Reactivity Series
The reactivity series is a list of metals arranged in order of their reactivity from most reactive to least reactive. Metals that are higher in the series can displace hydrogen from acids, which means they will react with acids to produce hydrogen gas.

### Step 2: Identify the Position of Metals in the Reactivity Series
The metals mentioned in the question are:
- Magnesium
- Potassium
- Aluminium
- Iodine

Now, we need to identify where each of these metals is positioned in the reactivity series:
- Potassium (most reactive)
- Sodium
- Calcium
- Magnesium
- Aluminium
- Zinc
- Lead
- Hydrogen
- Copper (least reactive)

### Step 3: Determine Which Metals Are Above Hydrogen
In the reactivity series, we see that:
- Potassium, Sodium, Calcium, Magnesium, and Aluminium are all above hydrogen.
- Iodine is a non-metal and is below hydrogen in the reactivity series.

### Step 4: Conclusion
Since the question asks which metal would react vigorously with dilute hydrochloric acid, we can conclude that:
- Potassium is the most reactive and will react vigorously with dilute hydrochloric acid.
- Magnesium and Aluminium will also react, but not as vigorously as Potassium.
- Iodine will not react with dilute hydrochloric acid.

### Final Answer
**Potassium** is the metal that would react vigorously with dilute hydrochloric acid.

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