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(a) Sulphur melts form a clear mobile li...

(a) Sulphur melts form a clear mobile liquid at `119^@ C` but on further heating to `180^@ C`, it becomes viscous. Why ?
(b) `SOCl_2` can act as a weak Lewis acid as well as a weak Lewis base. Explain.

Text Solution

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(a) Up to `119^@ C`, sulphur exists as `S_8` molecules which can roll over one another to form a mobile liquid. However, when this liquid is further heated to `180^@ C`, the cleavage of ring structure occurs and zig-zig open chains are formed which get interwound and tangled togther and hence sulphur becomes more viscous.
(b) Like nitrogen in ammonia, sulphur has two lone pair of electrons which it can donate, hence it acts as a weak base.
`SOCl_2` has also empty d-orbitals which can accommodate electron pairs from bases and hence acts as a weak acid.
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