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Q.
The reagent that can be used to differentiate $HCOOH$ and $CH_3COOH$ is
UP CPMTUP CPMT 2010Aldehydes Ketones and Carboxylic Acids
Solution:
Formic acid being a powerful reducing agent is easily able to reduce ammoniacal silver nitrate
$HCOOH + Ag_{2}O \xrightarrow{Heat}\underset{\text{Silver mirror}}{{2Ag↓+CO_{2}+H_{2}O}}$
$CH_{3}COOH \xrightarrow[{Reagent}] {{Tollen's}}$ no reaction