Which of the following is used to distinguish between acetophenone and acetaldehyde?

How will you convert butan$-2-$one to propanoic acid?

In which of the following reactions does an aromatic aldehyde react with an acid anhydride in the presence of the salt of the corresponding acid to form an unsaturated aromatic acid?

Base-catalyzed aldol condensation occurs with:

An optically active alkyl halide $C_4H_9Br$ $[A]$ reacts with hot $KOH$ dissolved in ethanol and forms alkene $[B]$ as the major product,which reacts with bromine to give dibromide $[C].$ The compound $[C]$ is converted into a gas $[D]$ upon reacting with alcoholic $NaNH_2.$ During hydration,$18 \ g$ of water is added to $1 \ mole$ of gas $[D]$ on warming with mercuric sulphate and dilute acid at $333 \ K$ to form compound $[E].$ The $IUPAC$ name of compound $[E]$ is $:$

Treatment of propionaldehyde with dil. $NaOH$ gives: