The hydrophilic-lipophilic value (HLV) of an oil-in-water emulsifying agent is in which range?

• A. 4-6
• B. 8-16
• C. 20-24
• D. 28-32

Answer: (B)

The important idea is how the emulsifier’s balance between hydrophilic and lipophilic parts affects the type of emulsion it stabilizes. A hydrophilic-lipophilic value (HLV) shows how water-loving versus oil-loving the molecule is. For oil droplets dispersed in water (oil-in-water emulsions), you want an emulsifier that is more hydrophilic so its head group sits in the water while the tail anchors into the oil droplet. That means the suitable emulsifier has a mid-to-high HLV, indicating a stronger preference for the aqueous phase.

So the range that best fits oil-in-water emulsifiers is the mid-to-upper portion of the HLV scale. Lower ranges correspond to lipophilic emulsifiers that favor water-in-oil systems, while very high values indicate extremely hydrophilic agents that may not optimally stabilize the oil droplets.