Question

In Tollen's test for aldehyde, the overall number of electron(s) transferred to the Tollen's reagent formula [Ag(NH₃)₂]⁺ per aldehyde group to form silver mirror is __________. (Round off to the Nearest Integer).

Hint:

Tollen's reagent is a mild oxidizing agent that identifies aldehydes by reducing $Ag^+$ to metallic silver.

Answer 1

Correct Answer: 2

Step 1: $RCHO + 3OH^- \rightarrow RCOO^- + 2H_2O + 2e^-$.
Step 2: $2[Ag(NH_3)_2]^+ + 2e^- \rightarrow 2Ag + 4NH_3$.
Step 3: For every 1 mole of aldehyde oxidized, 2 moles of $Ag^+$ are reduced to $Ag$. Total electrons transferred = 2.