In the given reaction sequence, the percentage of oxygen in compound $(Q)$ is . . . . . . $\%$. (Nearest integer)

Which product is not formed in the following reaction $:-$ $CH_3CHO + CH_3-CH_2-CHO \xrightarrow[\text {(ii) } \Delta]{\text {(i) } NaOH}$

Choose the incorrect statement among the following.
$A$. The reactivity of aromatic aldehydes and ketones is less than that of aliphatic carbonyl compounds towards nucleophilic addition reactions.
$B$. Benzaldehyde does not give Fehling's test.
$C$. The $\alpha$-$H$ atoms in ethanal are acidic in nature.
$D$. $p$-nitro benzaldehyde is less reactive than benzaldehyde towards nucleophilic addition reactions.

In the given reaction sequence,$Z$ is a mixture of alcohol and acid. The reaction for the conversion of $Y$ to $Z$ is:
$CH_3CH_2OH$ $\xrightarrow[443 \ K]{\text{Conc. } H_2SO_4} X$ $\xrightarrow[(2) \ Zn/H_2O]{(1) \ O_3} Y$ $\xrightarrow[(ii) \ H^+]{(i) \ \text{Conc. } NaOH} Z$

Which one of the following reactions can be used for the preparation of $\beta$-hydroxy acid derivatives?

Which of the following compounds does not react with concentrated alkali to give the corresponding alcohol and salt of carboxylic acid?