chem ...plz help

☆ 天與空 ★ ◤

2009-03-01 7:06 am

If ethyl 1-propanoate is refluxed with an excess of aqueous sodium hydroxide solution and the resulting solution is then distilled, the distillate contains mainly

A. ethanol

B. propan-1-ol

C. ethanoic acid

D. ethanol and propanoic acid

p.s. plz explain ..don't just give me the ans

thanks a lot

回答 (1)

老爺子

2009-03-01 8:00 am

✔ 最佳答案

The answer is A.

Ethyl propanoate hydrolyses in an excess of sodium hydroxide to give sodium propanoate and ethanol. The equation is:
CH3CH2COOCH2CH3 + NaOH → CH3CH2COONa + CH3CH2OH

The reaction mixture contain unreacted sodium hydroxide, sodium propanoate, ethanol and water.

Both unreacted sodium hydroxide and sodium propanoate are ionic compound, which have high boiling points and would not be separated in distillation.

Both ethanol and water have simple molecular structure, and their boiling points are low. However, ethanol (b.p. 78oC) has a lower boiling point than water (b.p. 100oC), and thus ethanol is evaporated more readily. Therefore, the distillate contains mainly ethanol.
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