Question

The HLB value required for O/W emulsions generally lies in between

• A. 1–3
• B. 8–18
• C. 7–9
• D. 3–6

Hint:

HLB (Hydrophilic-Lipophilic Balance) is a number that tells us how water-loving or oil-loving a surfactant is.

Answer 1

The Correct Option is B

Concept:
HLB (Hydrophilic-Lipophilic Balance) is a number that tells us how water-loving or oil-loving a surfactant is. A high HLB value means the surfactant is more water-soluble, while a low HLB value means it is more oil-soluble. The type of emulsion a surfactant can stabilise depends directly on this value.

Step 1: For an oil-in-water (O/W) emulsion, the oil droplets are dispersed inside a continuous water phase. To keep these droplets stable, we need a surfactant that prefers water, that is, one with a higher (more hydrophilic) HLB value.

Step 2: Surfactants with HLB values roughly in the range of 8 to 18 are water-loving enough to form and stabilise O/W emulsions. (For comparison, water-in-oil (W/O) emulsions need low HLB values, about 3 to 6.)

Answer: Option (2) — The HLB value required for O/W emulsions generally lies between 8–18. (2)