Explain why : Effervescence is seen on opening a bottle of soda water.

Explanation

**Step-by-Step Solution:**

1. **Understanding Soda Water Composition**: Soda water contains carbon dioxide (CO2) gas that is dissolved in water. This process occurs under high pressure, which allows a greater amount of CO2 to dissolve than would be possible at normal atmospheric pressure.

2. **High Pressure Environment**: When the bottle of soda water is sealed, the pressure inside the bottle is much higher than the pressure outside. This high pressure keeps the CO2 gas dissolved in the liquid.

3. **Opening the Bottle**: When you open the bottle, the pressure inside the bottle is suddenly released. This rapid change in pressure causes the CO2 gas that was dissolved in the water to become less soluble.

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