AIPMT – 2000

Hint: In phenoxide ion resonance takes place

The structure of ions of ethyl alcohol and phenol are as follows:

CH₃CH₂O^– and  

The ion of phenol which is known as phenoxide ion is resonance stabilized. In phenoxide ion, delocalisation of π-electrons takes place.
But in ethoxide ion it doesnot happen.

Hence, option one is the correct answer.