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JEE Main 2025 Jan 24 Shift 1, Chemistry Q13: Group 16 Elements: The Oxygen Family

JEE Main2025Jan 24, Shift 1Chemistry
Q.

The large difference between the melting and boiling points of oxygen and sulphur may be explained on the basis of

  1. A

    Atomic size

  2. B

    Atomicity

  3. C

    Electronegativity

  4. D

    Electron gain enthalpy

Solution

Oxygen exists as small discrete O molecules (atomicity 2), held together only by weak London forces, giving very low melting and boiling points.

Sulphur, in contrast, exists as puckered S rings (atomicity 8). The much larger S molecule has substantially greater surface area and polarisability, hence far stronger dispersion forces and dramatically higher melting and boiling points.

The decisive factor is the difference in molecular size that comes from the difference in atomicity. Option (2).

Concept behind this question

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