Home › NEET UG › Chemistry › Haloalkanes and Haloarenes › Among 1-bromobutane, 2-bromobutane, and 2-bromo-…
Among 1-bromobutane, 2-bromobutane, and 2-bromo-2-methylpropane (isomers, same MW), the boiling point order is:
AAll have the same boiling point
B2-bromo-2-methylpropane > 1-bromobutane > 2-bromobutane
C2-bromo-2-methylpropane > 2-bromobutane > 1-bromobutane
D1-bromobutane > 2-bromobutane > 2-bromo-2-methylpropane (branching decreases bp because surface area for van der Waals contact is smaller)
Answer & Solution
Correct answer: D. 1-bromobutane > 2-bromobutane > 2-bromo-2-methylpropane (branching decreases bp because surface area for van der Waals contact is smaller)
Among isomeric haloalkanes, **boiling point decreases with increased branching** because branching reduces the molecular surface area available for van der Waals contact. Linear 1-bromobutane > 2-bromobutane > the highly branched 2-bromo-2-methylpropane (lowest bp).
Related questions
$\mathrm{CHCl_3}$ (chloroform) on prolonged storage in the air may be partially oxidised tChlorobenzene ($\mathrm{C_6H_5Cl}$) is MUCH LESS reactive toward nucleophilic substitutionSAYTZEFF'S RULE for elimination reactions states thatWhen 1-bromopropane is heated with concentrated alcoholic KOH, the major product isA GRIGNARD REAGENT is formed by reacting an alkyl halide withThe IUPAC name of $\mathrm{(CH_3)_2CH{-}CH_2Br}$ isA SN2 reaction on a chiral carbon (with a single stereocentre) results inThe reactivity of haloalkanes toward nucleophilic substitution generally follows the order