Which of the following compounds will give silver mirror with ammoniacal silver nitrate? Choose the correct answer from the options given below :
- B and C only
- C and D only
- A, B and C only
- A only
Answer
(3) A, B and C only
Solution
Tollens' reagent is reduced to a silver mirror by compounds that are easily oxidised:
A. Formic acid, HCOOH: its H–C=O part acts like an aldehyde group, so it gives the mirror.
B. Formaldehyde, HCHO: an aldehyde, so it gives the mirror.
C. Benzaldehyde, C6H5CHO: an aldehyde, so it gives the mirror.
D. Acetone, CH3COCH3: a ketone, not oxidised, so no mirror.
∴ A, B and C only
Answer: (3)