Only an aldehyde having..... can undergo the aldol condensation.

Explain aldol condensation and the acidity of the $\alpha$-carbon of aldehydes and ketones. Provide the aldol condensation reactions for $ethanal$ and $propanone$.

What will be the product $S$ in the following reaction?
$CH_3COOH$ $\xrightarrow{SOCl_2} P$ $\xrightarrow[Anhyd. AlCl_3]{Benzene} Q$ $\xrightarrow{HCN} R$ $\xrightarrow{HOH} S$

The minimum number of carbon atoms in ketones which will show chain isomerism is:

The product $(A)$ of the reaction is:

An organic compound contains $69.77 \%$ carbon,$11.63 \%$ hydrogen and the rest is oxygen. The molecular mass of the compound is $86$. It does not reduce Tollens' reagent but forms an addition compound with sodium hydrogensulphite and gives a positive iodoform test. On vigorous oxidation,it gives ethanoic acid and propanoic acid. Write the possible structure of the compound.