Question

Which of the following compounds does not give a silver mirror with Tollen's reagent?

• A. Aromatic aldehyde
• B. Propanone
• C. Methanal
• D. Both (a) and (c) above

Answer 1

The correct option is B Propanone

Tollen's reagent refers to the chemical reagent which is used in the detection of an aldehyde functional group, an aromatic aldehyde functional group, or an alpha hydroxy ketone functional group in a given test substance.
Ketones don't give silver mirror with Tollens' reagent.
A postive test gives precipitate of elements silver.$RCHO+2\left[Ag\right(N{H}_3{)}_2{]}^{+}+3O{H}^{-}\to RCO{O}^{-}+2Ag\downarrow +2H_{2}O+4N{H}_3\text{Aldehyde}\text{Tollen's Reagent}\text{Carboxylate ion}\text{Silver mirror}$