The formation of N-methylacetamide from N-methylamine and acetic anhydride is an example of a nucleophilic acyl substitution reaction. Here's the step-by-step mechanism for this reaction:1. Nucleophilic attack: The nitrogen atom in N-methylamine CH3NH2 acts as a nucleophile, attacking the electrophilic carbonyl carbon in acetic anhydride CH3CO 2O . This results in the formation of a tetrahedral intermediate and breaking of the carbonyl double bond bond .2. Proton transfer: The negatively charged oxygen atom in the tetrahedral intermediate abstracts a proton from the nitrogen atom in the N-methylamine moiety, forming a hydroxyl group -OH and restoring the positive charge on the nitrogen atom.3. Leaving group departure: The hydroxyl group -OH in the tetrahedral intermediate acts as a leaving group, and the carbonyl double bond bond is reformed. This results in the expulsion of acetate ion CH3COO- as a leaving group.4. Proton transfer: The positively charged nitrogen atom in the N-methylacetamide CH3NHCOCH3 abstracts a proton from the acetate ion CH3COO- , forming the final N-methylacetamide product and an acetic acid molecule CH3COOH .Overall, the reaction can be summarized as follows:N-methylamine CH3NH2 + Acetic anhydride CH3CO 2O N-methylacetamide CH3NHCOCH3 + Acetic acid CH3COOH