The following reaction between ethyl alcohol and ethyl bromide forms diethyl ether via a substitution reaction (followed by deprotonation).cannot explain figure

see explanation below

Explanation:

The question is incomplete. The missing parts are a) determine the electrophylic site. b) determine the nucleophylic site.

In order to do this, we need to write the reaction and do the mechanism. The nucleophylic site will be the site where the nucleophyle attacks to form the product. In this case the site is the carbon next to the bromine. In this place the Oxigen which is the nucleophyle goes. The electrophyle is the site where one atom substract to complete it's charges. In this case, the electrophyle is usually the hydrogen, so the site will be next to the oxygen after the nucleophyle attack.

You can see it better in the attached picture.