During cooking, if water and mustard oil are mixed, oil floats on the top of water because:

The correct answer is the density of mustard oil is lesser than water.

Key Points

• Mustard oil floats on water because its density is lower than that of water, causing it to remain at the top.
• Density refers to the mass per unit volume of a substance. Mustard oil has a density of approximately 0.91 g/cm³, while water has a density of 1 g/cm³.
• Substances with lower density than water will naturally float when mixed, as gravity pulls denser substances downward.
• The immiscibility of mustard oil in water also prevents it from mixing, further contributing to its floating behavior.
• This phenomenon is a practical application of the principle of buoyancy, where less dense substances float over denser ones.

Additional Information

• Density: It is a measure of how much mass is contained in a given volume. The formula for density is Density = Mass / Volume.
• Buoyancy Principle: Objects float or sink based on their density relative to the fluid they are in. Less dense objects float, while denser ones sink.
• Immiscibility: Mustard oil is immiscible in water due to differences in polarity. Water is polar, while mustard oil is nonpolar, preventing them from forming a homogeneous mixture.
• Practical Application: Understanding density differences is used in cooking, oil spill management, and industrial processes where separation of immiscible substances is required.
• Surface Tension: Mustard oil exhibits surface tension, which helps it form droplets or layers when not mixed with water.