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Mystery #4Tier 1-2chemistry / reactions

Why does baking soda fizz when you add vinegar?

Pour vinegar onto a spoonful of baking soda and it erupts into a foaming, bubbling fizz, like a mini volcano. Neither one bubbles on its own. Where do all those bubbles suddenly come from?

A model volcano erupting with red foam from a baking soda and vinegar reaction, a box of sodium bicarbonate behind it.
Photo: Silviaelzi, Wikimedia Commons · CC BY 4.0 · via Wikimedia Commons

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