Aldol condensation involving $CH_3-CHO + CH_3-CHO$ gives the product:

Which of the following is an example of a conjugated diketone?

The correct order of rate of reaction toward nucleophilic addition reaction for the following compounds is:
$(a)$ $p-NO_2-C_6H_4-CHO$
$(b)$ $C_6H_5-CHO$
$(c)$ $p-OMe-C_6H_4-CHO$
$(d)$ $CH_3-CO-CH_2CH_3$
$(e)$ $C_6H_5-CO-C_6H_5$

When acetaldehyde is heated with Fehling solution,a red precipitate is formed. Which of the following is that?

In a set of reactions,an acid yielded a product $D$.
$CH_3COOH$ $\xrightarrow{SOCl_2} A$ $\xrightarrow[Anhyd. AlCl_3]{Benzene} B$ $\xrightarrow{HCN} C$ $\xrightarrow{H_3O^+} D$
Identify the product $D$.

Which of the following can be used to differentiate pentan$-2-$one and pentan$-3-$one?