What is the chemical composition of Tollen's reagent?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Ammoniacal Silver nitrate solution.
Tollens’ reagent is ammoniacal silver nitrate solution; it contains the diamminesilver(I) ion, \( \ce{[Ag(NH3)2]+} \). An aldehyde reduces this ion to metallic silver and is itself oxidised to the carboxylate ion:
\( \displaystyle \ce{RCHO + 2[Ag(NH3)2]+ + 3OH- -> RCOO- + 2Ag v + 2H2O + 4NH3} \)
Copper(II), not silver, is the oxidant of Fehling’s test. Q48 of this paper asks which compounds give that test: aromatic aldehydes such as benzaldehyde give the Tollens’ test but not the Fehling’s test.
NCERT (2026-27 edition):
Tollens’ Test
Note: The same/similar question has been asked in different years by NTA as per the details given below:
| 2026 | 2025 | 2024 | 2023 | 2022 |
|---|---|---|---|---|
| – | 29-05 S1 13-05 S2 | – | – | – |