0. The HLB scale is based on the arbitrary range between 0 and 20(Sodium lauryl sulfate is a well-known exception with an HLB valueof 40).

   •  Emulsifiers with a low HLB (1-6) are lipophilic andpromote the formation of w/o emulsions.

   •  Emulsifiers with a high HLB (9-20) are hydrophilic andpromote the formation of o/w emulsions.

   •  Emulsifiers with HLB values between 7 and 9 may promoteeither.

Q1 a) Calculate Required HLB for the oil phase (remembering thatpercentages in the above formula represent the percentages inthe final product, not in the oil phase).

b) Calculate HLB values of surfactant mixtures in Table 1below.

c) Predict emulsion nature (o/w or w/o) and rank emulsions inthe order of expected stability* (allocating a rank of 1 tothe most stable emulsion, 2 to the next most stable etc).

Oil-in-water (o/w) emulsions have been prepared in advance according to the following formula: Ingredients Percentage Mass (g) Ingredients 20% w/w 8 Light Liquid Paraffin (LLP) Arachis Oil (AO) 5% w/w 2 Surfactants (total) Purified Water Percentage 5% w/w to 100% w/w Mass (g) 2 28