Assertion :Among isomeric alkanes, branching increases the boiling points. Reason: branching lowers the intermolecular van der waals force of attraction.

Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

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Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

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Assertion is correct but Reason is incorrect

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Assertion is wrong but Reason is correct.

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Solution

The correct option is D Assertion is wrong but Reason is correct.
Among isomeric alkanes, branching decreases the boiling points. This is due to the fact that branching of the chain makes the molecule more compact and thereby decreases the surface area.
The intermolecular forces (often called van der Waal's forces) depend on attractions caused by quantum fluctuations in the surface electrons of the molecule. The larger the surface area, the more opportunity for such attractions and a stronger force.
Therefore, the intermolecular attractive forces depend upon the surface area and can also become small in magnitude on account of branching. Consequently, the boiling points of the branched chain alkanes are less than the straight chain isomers.

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