Order of hydrolysis for the following

(I) RCOCI

(II) RCOOR

(III) RCONH₂

(IV) (RCO)₂O

Of all the acid derivatives, acid chlorides, i.e. CH₃COCI is most reactive.
The order of reactivity of acid derivatives decreases in the following order,

$\mathrm{RCOCl}>(\mathrm{RCO}{)}_2\mathrm{O}>\mathrm{RCOOR}>{\mathrm{RCONH}}_2$