MHTCET 16 Apr 2026 Shift 1 Paper

Concept:Aldehydes reduce Tollens' reagent to metallic silver, producing a silver mirror on the test tube.Explanation:Tollens' reagent contains the diamminesilver(I) complex ion, $\left[\mathrm{Ag}\left(\mathrm{NH}_{3}\right)_{2}\right]^{+}$.When an aldehyde is warmed with this reagent, the aldehyde is oxidised to a carboxylate ion.Simultaneously, silver ions are reduced to metallic silver, $\mathrm{Ag}$, which deposits as a shiny layer on the inner walls of the test tube.The reaction is:$\mathrm{RCHO} + 2\left[\mathrm{Ag}\left(\mathrm{NH}_{3}\right)_{2}\right]^{+} + 3\mathrm{OH}^{-} \rightarrow \mathrm{RCOO}^{-} + 2\mathrm{Ag} + 4\mathrm{NH}_{3} + 2\mathrm{H}_{2}\mathrm{O}$This shiny silver deposit on the test tube sides is called the silver mirror.It is the characteristic observation of Tollens' test for aldehydes, confirming their presence.Answer:Formation of an Ag layer on the sides of the test tube upon addition and warming of the reagent, i.e., Option B.