Question

which substance has the weakest attractive forces based on the provided size of the molecule? c₂₀h₄₂ c₄h₁₀ c₈h₁₈

Explanation:

Step1: Understand intermolecular forces

In non - polar hydrocarbons, London dispersion forces are the main attractive forces. These forces increase with the size of the molecule.

Step2: Compare molecule sizes

$C_4H_{10}$ has the smallest number of carbon and hydrogen atoms among $C_{20}H_{42}$, $C_4H_{10}$ and $C_8H_{18}$. Smaller molecules have fewer electrons, resulting in weaker London dispersion forces.

Answer:

$C_4H_{10}$