Q. Which of the following can be used to differentiate between aldehyde and ketone?
A) Ammoniacal $AgNO_{3}$
B) Ammoniacal $AgNO_{3}$ in presence of tartarate ion
C) $I_{2}$ in the presence of base
D) Ammoniacal $AgNO_{3}$ in the presence of citrate ion
Explanation
(a)
Aldehydes are oxidised by weak oxidising agents like Tollen’s reagent (which is ammoniacal $AgNO_{3}$) but ketones cannot be oxidised by them.
$RCHO + 2\left\lbrack Ag\left( NH_{3} \right)_{2} \right\rbrack^{+}3OH^{-}\overset{\ \ \ \ NH_{4}OH\ \ \ \ \ \ \ }{\rightarrow}RCO\overline{O} + 2Ag \downarrow + 2H_{2}O + 4NH_{3}$
Aldehyde Tollen’s reagent silver mirror
Ketone + Tollen’s reagent $\rightarrow$ no reaction.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.