汽水是不是一定酸的?為什麼?

是因為汽水有碳酸如果冇左碳酸「有汽飲品」就會冇汽。
因為在汽水廠其實格硬以非常高的气壓去把更多的CO2溶入水中形成碳酸。
CO2+H2O=H2CO3
因此當汽水回到常壓的時候它就會把之前因為高壓先溶到入水的CO2放番出去因此會好似有汽。
而H2CO3可以在水中電離成2H+和CO3(2-)
H+又是只酸,因此所有「有汽飲品」都必要是酸的

有汽飲品 refers to those which will evolve carbon dioxide after exposure in air.
Although carbon dioxide is acidic gases, it doesn't mean that 有汽飲品 is always acidic.
Coca-cola is acidic because the carbon dioxide is directly dissolve in the solution to form carbonic acid but some other 有汽飲品 is not acidic because it contains sodium carbonate or sodium hydrogencarbonate only. This compound also evolve carbon dioxide under the exposure.

只要主要成份有"碳酸水"就酸

soda水就不酸, 如swepp