Final answer:
The correct ranking in order of increasing surface tension for C₆H₁₂, C₄H₁₀, and C₈H₁₈ is C₆H₁₂ < C₄H₁₀ < C₈H₁₈.
Step-by-step explanation:
The correct ranking in order of increasing surface tension for C₄H₁₀, C₆H₁₂, and C₈H₁₈ is C₆H₁₂ < C₄H₁₀ < C₈H₁₈.
Surface tension is a property of liquids that quantifies the force needed to break the surface of the liquid.
It is determined by intermolecular forces, with stronger forces resulting in higher surface tension. In this case, the length of the hydrocarbon chain affects the surface tension.
As the chain gets longer (from C₄H₁₀ to C₈H₁₈), there are more London dispersion forces between molecules, leading to higher surface tension. Therefore, C₆H₁₂ has the lowest surface tension, followed by C₄H₁₀, and C₈H₁₈ has the highest surface tension.