Oxidation of acetaldehyde with selenium dioxide produces:

Oxidation of propanone with selenium oxide produces

How is carbon dioxide produced?

Oxidation of aniline with manganese dioxide and sulphuric acid gives :

A compound 'A' on oxidation gave acetaldehyde , then again on oxidation gave acid . After first oxidation it was reacted with ammoniacal AgNO_3 then silver mirror was produced. A is likely to be

Oxidation By Selenium Dioxide