Question #69afb

1 Answer

b) #"pH" = 3#

Explanation:

At #"pH"= 3#, glutamate is in the zwitterionic form:

#"HOOC"-"CH"_2-"CH"_2-"CH"-("NH"_3^(+))("COO"^(-)) #

and has no net charge, whilst at #"pH"= 2.19#, it has one half net positive charge, at #"pH"= 4.25#, it has about half net negative charge. At #"pH"= 7# it has one net negative charge and at #"pH"= 9.25#, it has a one and half net negative charge.

The more net charges (positive or negative) on the molecule, the better will be the solvation by polar solvents like water.