I've read in [Wikipedia](https://en.wikipedia.org/wiki/Mesomeric_effect#:~:text=The%20mesomeric%20effect%20in%20chemistry,present%20on%20an%20adjacent%20atom) about +M strength of groups which goes: > –O __-__ > –NH2 > __–NHCOR > –OR__ > –OCOR > –Ph > –CH3 > –F > –Cl > –Br > –I Now in every other website and the book in GOC by OP Tandon states that in terms of +M strength: [![enter image description here][1]][1] [1]: https://i.sstatic.net/w9Sdr.jpg # My question: # Can you please verify the series and explain if -OH actually has less activity than -NHCOR? * Also since in -NH of -NHCOR there is an EWG(Electron withdrawing group) which is -COCH3 which should decrease the activity of the group appreciably.