Some have only one alpha position, some have more than one. Draw an enol for each of the compounds listed above. You could say that the alpha hydrogen is acidic. Explain why, and draw a picture to illustrate this. Enolate ions are nucleophilic, and do the usual SN2 chemistry.
Esters enolize too , and their enolate ions do the same things that ketone-enolates do.
The enolate is a nucleophile and does SN2-type chemistry, and NACC attack type of chemistry. Carboxylic Acids and Derivatives Chapter Ten introduces carboxylic acids and their derivatives. The chemistry is very similar to that of the ketones and aldehydes because of the presence of the carbonyl group. Most of these reactions involve a NACC Attack. Nitriles are a little different, but their chemistry follows the same pattern.