Chemistry · Classification, isomerism, IUPAC nomenclature, general methods of preparation, properties and reactions
Assertion Boiling point of pentane is higher than 2,2-dimethylpropane. Reason Th
Assertion Boiling point of pentane is higher than 2,2-dimethylpropane. Reason There is steady increase in boiling point with increase in molecular mass.
- A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
- B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
- C. Assertion is correct but Reason is incorrect
- D. Both Assertion and Reason are incorrect
Step-by-step solution
Pentane and 2,2-dimethylpropane are structural isomers with the same molecular formula (C5H10), so they have the same molecular mass. The higher boiling point of pentane (straight-chain) compared to 2,2-dimethylpropane (branched) is due to greater surface area and stronger London dispersion forces, not molecular mass. The Reason incorrectly states a steady increase in boiling point with molecular mass, but since both have identical mass, it does not explain the difference. Thus, Assertion is true, Reason is false.
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