Transcript Exercise 17.1

CONCEPTUAL EXAMPLE 17.1
Classification of Surfactants
Classify each of the following surfactants as anionic, cationic, nonionic, or amphoteric.
a. CH3(CH2)14CH2N+(CH3)3Cl–
b. CH3(CH2)13O(CH2CH2O)7SO3–Na+
c. CH3(CH2)12CH2NH2+CH3COO–
d. CH3(CH2)12CON(CH2 CH2 OH)2
Solution
a.
b.
c.
d.
The N atom of the large, active part bears a positive charge; this is a cationic surfactant.
(The counter ion is Cl–.)
There is a negative charge on the group of the active part, making this an anionic surfactant.
(The counter ion is Na+)
This substance has both a positive charge (on the N atom) and a negative charge (on the COO – group),
making this an amphoteric detergent.
This substance has neither a positive charge nor a negative charge; it is a nonionic surfactant.
Exercise 17.1
Classify each of the following surfactants as anionic, cationic, nonionic, or amphoteric.
a. CH3(CH2)8—C6H4—O(CH2 CH2O)9H
b. CH3(CH2)14COO–K+
c. CH3(CH2)9—C6H4 — SO3–Na+
d. CH3(CH2)12CH2N+(CH3 )3Cl–