Question

Explain the reaction of 1° and 2° alcohol with oxidising agent chromic anhydride (CrO₃).

Answer 1

1° alcohol on oxidation in the presence of CrO₃ forms aldehyde:
\[\ce{\underset{(1° alcohol)}{R - CH2 - OH} ->[CrO3][(O)] \underset{(Aldehyde)}{R - CHO}}\]

2° alcohol on oxidation in the presence of CrO₃ forms ketone:
\[\begin{array}{cc}
\ce{R - CH - R' ->[CrO3][(O)] R - C - R'}\\
|\phantom{..................}||\phantom{.}\\
\phantom{.}\ce{\underset{(2° alcohol)}{OH}\phantom{...........}\underset{(Ketone)}{O}}\phantom{..}
\end{array}\]