Part B: A pinacol- pinacolone rearrangement: benzopinacolone from benzopinacol Solution a ) The photochemical light having shorter wawelenght ( < 200 cm -1 ) have a high energy sufficient to breck covalent bonds.If we use pyrex vessel it cannot withstand to such aa energy & will be brocken down.For the stability of pyrex vessel the waveleght required is above 200 cm -1 .The quartz vessel is stable to such photochemicals energy & therefore used in photochemical reaction. b ) the light is absorbed & passed through pinacolon mixture without initiating the reaction & hence the measurable conversion is less & therefore precipitated out. c ) The most of the impurities in the precipitates are dissolved in 95 % ethanol & we get pure precipitates. d) The protonation of hydroxyl group by acid makes leaving group & expel oit as water. The one of the phenyl group is the transfered to electron deficient carbon atom makinf C-O double bond.& hence reaction is irreversible .

1. Part B: A pinacol- pinacolone rearrangement: benzopinacolone from benzopinacol
Solution
a ) The photochemical light having shorter wawelenght ( < 200 cm -1
) have a high energy
sufficient to breck covalent bonds.If we use pyrex vessel it cannot withstand to such aa energy &
will be brocken down.For the stability of pyrex vessel the waveleght required is above 200 cm -1
.The quartz vessel is stable to such photochemicals energy & therefore used in photochemical
reaction.
b ) the light is absorbed & passed through pinacolon mixture without initiating the reaction &
hence the measurable conversion is less & therefore precipitated out.
c ) The most of the impurities in the precipitates are dissolved in 95 % ethanol & we get pure
precipitates.
d) The protonation of hydroxyl group by acid makes leaving group & expel oit as water. The one
of the phenyl group is the transfered to electron deficient carbon atom makinf C-O double
bond.& hence reaction is irreversible