In the given reaction,what will be $A$ and $B$ respectively?
$(CH_3)_2CO$ $\xrightarrow{NaCN/HCl} A$ $\xrightarrow{H_3O^+} B$

The product $(B)$ in the given reaction is:

An alkene $(A)$ $C_{16}H_{16}$ on ozonolysis gives only one product $(B)$ $C_8H_8O$. $(B)$ can also be obtained by the hydrolysis of the product obtained from the reaction between cyanobenzene and $CH_3MgBr$. $(A)$ shows geometrical isomerism and decolourises $Br_2$ water. $(B)$ on treatment with $SeO_2$ produces $(C)$. Which statement is not correct about $(C)$?

An organic compound $P$ having molecular formula $C_6H_6O_3$ gives a ferric chloride test and does not have an intramolecular hydrogen bond. The compound $P$ reacts with $3$ equivalents of $NH_2OH$ to produce oxime $Q$. Treatment of $P$ with excess methyl iodide in the presence of $KOH$ produces compound $R$ as the major product. Reaction of $R$ with excess iso-butylmagnesium bromide followed by treatment with $H_3O^{+}$ gives compound $S$ as the major product. The total number of methyl $(-CH_3)$ groups in compound $S$ is . . . .

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

Which of the following compounds does not give Tollen's test?