Acetaldehyde reacts with semicarbazide,the product will be:

Which of the following tests can be used to differentiate acetaldehyde and acetone?

Identify the correct option regarding the distinction between pairs of compounds.

The intermediate $J$ in the following Wittig reaction is

Consider the following sequence of reactions.
$C_6H_5COONa$ $\xrightarrow[\Delta]{NaOH/CaO} X$ $\xrightarrow[\text{Anhy. } AlCl_3]{CO/HCl} Y$ $\xrightarrow[NaOH]{\text{conc. }} A + B$.
If $A$ is the reduction product of $Y$,what is $B$?

$CH_3CHO$ $\xrightarrow[5\,^{\circ}C]{10\%\,NaOH}$ $\xrightarrow[\Delta]{}$ $\xrightarrow[Ni]{H_2} (A)$; Product $(A)$ of the reaction is