(A) : Melting point of n - pentane > Isopentane > Neopentane
(R) : As branching increases London dispersion forces become stronger

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(A) is true but (R) is false

Both (A) and (R) are correct and (R) is the correct explanation of (A)

Both (A) and (R) are false

Both (A) and (R) are correct but (R) is not the correct explanation of (A)

answer is C.

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Detailed Solution

The melting point of n-pentane is higher than that of isopentane and neopentane because n-pentane has a linear structure and can pack more tightly in the solid state, resulting in stronger intermolecular forces.
In contrast, isopentane and neopentane have branched structures that prevent tight packing, resulting in weaker intermolecular forces and lower melting points.
Statement R is false because branching decreases London dispersion forces, rather than increasing them.
London dispersion forces arise due to the temporary dipoles that form between non-polar molecules.
When a molecule is branched, its surface area decreases, which reduces the likelihood of temporary dipoles forming and weakens the London dispersion forces.
Therefore, as branching increases, the strength of London dispersion forces decreases, which leads to weaker intermolecular forces and lower melting points.

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