Which element reacts most explosively in water? Li or K

Explanation

To determine which element, lithium (Li) or potassium (K), reacts most explosively with water, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Elements**: We are comparing lithium (Li) and potassium (K), both of which are alkali metals.

2. **Understand Alkali Metal Reactivity**: Alkali metals are known for their reactivity with water. The reactivity of alkali metals increases as you move down the group in the periodic table.

3. **Compare Lithium and Potassium**:
- Lithium is located higher in the group compared to potassium.
- Potassium, being lower in the group, has a larger atomic radius and a lower ionization energy, which makes it more reactive.

4. **Reactivity with Water**:
- When alkali metals react with water, they produce hydroxides and hydrogen gas.
- The general reaction can be represented as:
\[ 2M + 2H_2O \rightarrow 2MOH + H_2 \]
- For potassium (K), the reaction is:
\[ 2K + 2H_2O \rightarrow 2KOH + H_2 \]
- This reaction is more vigorous and produces hydrogen gas rapidly, which can ignite due to the heat generated.

5. **Conclusion**: Since potassium reacts more vigorously and explosively with water compared to lithium, we conclude that potassium (K) reacts most explosively in water.

### Final Answer:
Potassium (K) reacts most explosively in water compared to lithium (Li).

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