State the reason for the following :
Sodium or potassium metals are kept immersed under kerosene.

Explanation

**Step-by-Step Solution:**

1. **Identify the Metals**: The metals in question are sodium (Na) and potassium (K). Both belong to the alkali metals group in the periodic table.

2. **Understand Their Reactivity**: Sodium and potassium are known for their high reactivity. They have one electron in their outermost shell (3S1 for sodium and 4S1 for potassium), which makes them very eager to lose that electron and react with other substances.

3. **Reactivity with Oxygen**: These metals react vigorously with oxygen present in the atmosphere. This reaction can produce heat and light, often resulting in combustion, which means they can catch fire easily.

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