MHT CET Chemistry Question (2026) — Solution

Step-by-step solution

London dispersion forces increase with an increase in molecular mass and the surface area of the molecule. Methane (CH_4) and ethane (C_2H_6) have lower molecular masses compared to n-pentane and neo-pentane (C_5H_ 12 ), resulting in weaker dispersion forces. Between n-pentane and neo-pentane, n-pentane is a straight-chain alkane, whereas neo-pentane is highly branched and nearly spherical. The straight-chain structure of n-pentane provides a larger surface area for intermolecular contact compared to the compact structure of neo-pentane. Therefore, n-pentane has the strongest London dispersion forces among the given hydrocarbons. Answer: n-pentane