Question

Oil spreads on cold water but may remain as a drop on hot water because:

• A. a) surface tension of oil is more than that of cold water
• B. b) surface tension of oil is less than that of cold water
• C. c) surface tension of oil is more than that of hot water
• D. d) Both (b) and (c)

Answer 1

The correct option is D

d) Both (b) and (c)

Surface tension of oil is less than cold water, and hence, oil spreads over cold water. However, surface tension of oil is greater than that of hot water, and hence, its shape remains as a drop.