Hydrophobic Effect and HLB Quiz

What is the hydrophobic effect?

• The attraction of hydrophobic molecules to water

• The tendency of water to repel nonpolar substances

• The dispersion of hydrophilic molecules in water

• The ability of water to form hydrogen bonds with amphiphiles

In an amphiphilic molecule, the hydrophobic region is typically:

• Water-attracting

• Water-repelling

• Polar

• Hydrogen-bonded to water

What is the critical micelle concentration (CMC)?

• The concentration of water in a micellar solution

• The point at which an amphiphilic solute completely dissolves in water

• The concentration at which micelles start to form

• The concentration of amphiphiles that is not affected by the hydrophobic effect

Which of the following is a common example of an amphiphilic compound?

• Sodium chloride (table salt)

• Lithium

• Phospholipid

• Hexane

The hydrophilic part of an amphiphilic molecule interacts favorably with water due to its ability to:

• Form hydrogen bonds

• Disrupt the water's structure

• Repel water molecules

• Enhance hydrophobic interactions

In biological membranes, what role does the hydrophobic effect play in the organization of lipids?

• It promotes the even distribution of lipids.

• It causes lipids to dissolve in the aqueous environment.

• It leads to the formation of lipid bilayers.

• It enhances the solubility of hydrophilic molecules.

Which type of surfactant has a positively charged hydrophilic group?

•  Anionic surfactant

• Cationic surfactant

• Nonionic surfactant

• Amphoteric surfactant

An example of an anionic surfactant commonly used in personal care products is:

• Cetyltrimethylammonium chloride

• Nonylphenol ethoxylate

• Sodium lauryl sulfate

• Polysorbate 80

High HLB surfactants are typically used in:

• Water-in-oil (W/O) emulsions

• Oil-in-water (O/W) emulsions

• Both W/O and O/W emulsions

• Antifoaming agents

What is the key characteristic that determines whether a surfactant has a high or low HLB value?

• Its charge

•  Its molar mass

• Its balance between hydrophilic and lipophilic properties

• Its origin (natural or synthetic)