Question

How would you ascertain that a given emulsion is of o/w or w/o type?

Answer 1

To ascertain whether an emulsion is oil-in-water (o/w) or water-in-oil (w/o), the following tests are used:

1. Dilution test: Add water; if it mixes, the emulsion is o/w; if not, w/o. Similarly, adding oil that mixes indicates w/o.
2. Conductivity test: Add electrolyte and measure conductance; increase indicates o/w, no change indicates w/o.
3. Dye test: Add oil-soluble dye; color change means w/o, no change means o/w.

These simple tests help identify the emulsion type effectively.