Key Concepts—Aldehydes and Ketones—Nucleophilic Addition

The reaction is reversible. Equilibrium favors the product only with less stable carbonyl compounds (e.g., H2CO and CI3CCHO). 

Step [1] is best with CH3X and RCH2X because the reaction follows an Sn2 mechanism. 

A strong base is needed for proton removal in Step [2]. 

The reaction is acid cataiyzed and is the reverse of acetai synthesis. 

A large excess of H2O drives the equiiibrium to favor the products. 

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