係咪所有polar compound 都可以溶喺水架, 點解ge????

因為水分子本身是polar molecules
As long as the compound is polar, it can readily disolved in water.
Due to 「Like dissolves like」
As long as the intermolecular attraction of the compound is the same with that of the water molecules,
the compound can be dissolved in water.

2008-03-17 00:27:24 補充：
Like dissolves like 中文我都不太清楚, 大概解作「有相似吸引力的不同物質可以互相融合」
想回應上面果位朋友的答案.
Fatty acids have vey long hydrocarbon chains
These side chains are water insoluble(不溶於水的)
So fatty acids are insoluble in water.

no. many polar organic compounds do not dissolve in water.
like fatty acid, it is polar but it doesn't dissolve in water.
it is because the carbon chain is long. the covalent character
is higher. in the case of ethanoic acid , it is soluble in water.
it is because the carbon chain is short. the covalent character
is low.