Relative inductive effects with reference to hydrogen, in decreasing order of −I effect or increasing order of +I effect, as follows:
–+NH3> –NO2> –SO2R> –CN>
–SO3H> –CHO> –CO> –COOH>
−F> –COCl> −CONH2> –Cl>–Br>
–I> –OR> −OH> −NR2
> –NH2> –C6H5> –CH=CH2> –H