【問題】有機化學溶解度

[cj2340 10]

Which of the substances below is least soluable in water?

A. CH2OHCHOHCH2OH

B. CH3COCH3

C. CH3CH2COOH

D. CH3COOCH3

看到這個問題的時候我上網查了一下

"對水的溶解度：CH3CH2COOH＞CH3CH2CH2OH＞CH3COOCH3"

http://140.127.36.251/aa/show.asp?questionid=12

又看到

"Esters participate in hydrogen bonds as hydrogen-bond acceptors, but cannot act as hydrogen-bond donors, unlike their parent alcohols. This ability to participate in hydrogen bonding makes them more water-soluble than their parent hydrocarbons. "

http://en.wikipedia.org/wiki/Ester

到底哪一個才是對的啊?

[psi 10]

都對阿...而且就我所知A.B.C跟水可以無限互融.

[react 10]

可不可以把問題解釋清楚

我看不來有什麼矛盾啊

[cj2340 10]

抱歉這麼晚才回

我覺得矛盾的地方是

他說Ester is more water-soluble than their parent hydrocarbons.

我假定他所說的parent hydrocarbons是指原本組成ester的alcohol和carboxylic acid,

如果是這樣的話,那便是說ester比alcohol and carboxylic acid更溶於水?

中英雜打好累(倒)

[cj2340 10]

我了解他的意思了

That statement is poorly worded. It should mean that an ester based on 12 carbons (total) is more water soluble than a hydrocarbon with 12 carbons. Not a very useful statement in my opinion since esters are not generally recognized as being 'soluble' in water but water does have an affinity for esters and will dissolve in them at the rate of several hundreds of parts per million.

I have seen that language also used (more correctly) to describe the solubility of alcohols. It is true that alcohols are more soluble than their parent hydrocarbons. The statement attibuted about esters coming at the heels of a statement about alcohols further confuses the issue... not good teaching in my opinion.