What is Popoff's Rule ?

Popoff's or Popov's Rule ?

Oxidation of unsymmetrical ketone are governed by Popoff's rule which states that during the oxidation of an unsymmetrical ketone, the cleavage of the C-CO bond is such that the keto group always stays with the smaller alkyl group. Aleksandr Popov, a Russian chemist, gives Popoff's rule in 1871 while working with August Kekulé and E.K. Theodor Zinkce in Bonn.

For example, CH₃CH₂COCH₂CH₂CH₃ on oxidation with HNO₃ gives two moles of propanoic acid.