lime water 加CO2問題

lime water 加CO2 turn milky:
Ca(OH)2(aq) + CO2(g) --------> CaCO3(s) + H20(l)

再加excess CO2就會變返colourless
CaCO3(s) + H20(l)+CO2(g) --------> Ca(HCO3)2(aq)
The formed product is calcium hydrogencarbonate


To jolielam [小學級 5 級]."要注意的是 limewater 無論加多少 CO2，它只會 turn milky 而不會變返colourless。" Your concept is wrong! This is a common chemical test for CO2(g) and always examined in public examination. I hope you know that once CO2 is added in excess, the insoluble CaCO3 will become soluble again. You can find this equation easily in chem. book.


I hope both of you know what I am taking about and find this information helpful

calcium hydroxide + carbon dioxide → calcium carbonate + water
Ca(OH)2 + CO2 → CaCO + H2O
當calcium hydroxide + carbon dioxide時,calcium carbonate和水會產生.由於calcium carbonate 不能溶於水,所以個solution turn milky

calcium carbonate + water + carbon dioxide →water+calcium hydrogencarbonate
由於calcium hydrogencarbonate 可溶於水，所以lime water 就會變返colourless

calcium hydroxide + carbon dioxide → calcium carbonate + water
Ca(OH)2 + CO2 → CaCO + H2O

要注意的是 limewater 無論加多少 CO2，它只會 turn milky 而不會變返colourless。

calcium carbonate + hydrochloric acid--> calcium chloride + carbon dioxide + water

其實呢個應該係無equation
因為佢係一個化學反應