Same chapter3 marksDifficulty: Medium
Why is ammonia a stronger base than phosphine?
p-Block Elements
3 marksDifficulty: Medium
Why is sulphur hexafluoride known but not sulphur hexachloride?
Original Khojo Papers practice question — not from a past board paper.
Answer
Fluorine is small enough for six atoms to fit round a sulphur atom without crowding, and it is the most electronegative element so it stabilises the high oxidation state. Chlorine atoms are much larger, so six of them cannot be accommodated round sulphur.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
Steric crowding, not the energy of bond formation, is the deciding factor.
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