on reactivity of derivatives, I got the following answer for increasing reactivity toward nucleophilic acid substitution: sodium acetate, ethyl acetate, ethyl thioacetate, acetic anhydride, acetonitrile, acetyl chloride. I’m not sure if that is right. (Almost. Move acetonitrile in between sodium acetate and ethyl acetate - GS).

sodium acetate, acetonitrile, ethyl acetate, ethyl thioacetate, acetic anhydride, acetyl chloride (Yes - GS).

Can you explain why? (Acetonitrile has a strong triple bond, which is supposed to be broken by the nucleophile, so it is more reactive only than very unreactive negatively charged sodium acetate. Also there is no leaving group in acetonitrile, which pushes the reaction forward. - GS).

Thank you!