Question

Assign appropriate reason for the following observation.

SF₆ is not easily hydrolysed whereas SF₄ is easily hydrolysed.

Assign appropriate reason for the following observation.

SF₆ is not easily hydrolysed, whereas SF₄ is readily hydrolysed.

Answer 1

1. SF₆ is not easily hydrolysed because all six fluorine atoms are strongly bonded to sulphur, and the sulphur atom has a stable octahedral structure with no lone pairs on sulphur, making it sterically hindered and resistant to attack by water.
2. SF₄ is easily hydrolysed because sulphur in SF₄ is in a +4 oxidation state with one lone pair, giving it a trigonal bipyramidal structure that is less stable and more reactive toward water.
3. In SF₄, the presence of a lone pair on sulphur weakens the S-F bonds and allows water to attack more readily, causing hydrolysis.
4. In contrast, SF₆ lacks such a lone pair and has more symmetrical bonding, making hydrolysis difficult.

Hence, steric hindrance and electronic structure differences cause SF₆ to resist hydrolysis while SF₄ undergoes it easily.