Question

What is responsible for giving positive results with Tollens' test?

Answer 1

The Tollens test is used to determine whether a particular compound is a ketone or an aldehyde. A positive result of the Tollens test would indicate the presence of aldehydes. This would result into the presence of a silver precipitate, normally referred to as 'silver mirror'.
tollens reagnet -[Ag(NH3)2]+
[Ag(NH3)2]+ (aq) + e− → Ag (s) + 2 NH3 (aq)
RCHO (aq) + 3 OH− → RCOO− + 2 H2O + 2 e−
this reaction is specific to aldehyde and ketone wont result this