Question

Compare the acidities of amide `(R-underset(O)underset(||)(C)-NH_(2))` and sulphonamide `(R-underset(O)underset(||)overset(O)overset(|)S-NH_(2))`

Answer 1

The conjugate base of sulphonamide is stabilised by the delocalisation of the negative charge to two `O` atoms, whereas in amide the delocalisation in possible to only one `O` atom Hence, sulphonamides are more acidic than amides.
`R-underset(O)underset(||)overset(O)overset(||)S-ddotNH_(2)hArr [R-overset(O)overset(||)underset(O)underset(||)S-underset(..)overset(ddotTheta)NHharr R-overset(O^(Theta))overset(|)underset(O)underset(||)S=ddotNH harrR-underset(O_(Theta))underset(|)overset(O)overset(||)S=ddotNH]`