Question

Is functional group (hydroxyl, amino, sulfhydryl, phosphate, carboxyl) acidic or basic? Can you explain it really easy like how do you know which one is more basic? I have to explain it to a person who is not majoring in this stuff. Also, is there any real world application that we use functional groups to increase/ decrease acidity? or any similar situation?

 

Answer 1

amino groups are basic and hydroxyl, sulfhydryl, phosphate, carboxyl groups are acidic

There are three different definitions that determine wether something is acidic or basic.

A base accepts H and an acid gives off H
A base donates an electron and an acid accepts electrons

This structural difference does not change the electronegativity or atomic radius of the oxygen atoms that share an electron pair with a proton, nor does it change the number of resonance contributors. A new explanation is in order. Recall that the role of a base is to share an electron pair with a proton to form a new covalent bond. Recall that electronegativity is the measure of an atom's attraction for electrons. The higher the electronegativity, the greater the attraction. We can extend this idea further and conclude that atoms with higher electronegativity will be less inclined to share their electrons with a proton. Thus, increasing electronegativity of the atom that shares an electron pair will decrease basicity. Weaker bases have stronger conjugate acids, so we conclude that as electronegativity of an atom increases the acidity of the attached proton also oncreases.

amine group is more basic. it has one electron pair. it is easily donates the electrons to the electrophiles.