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

The reactivity towards nucleophilic addition reaction of
$(I) HCHO$,
$(II) CH_3CHO$,
$(III) CH_3COCH_3$ is

Identify the correct statements about $Z$ in the following reaction sequence:
$C_2H_5NH_2$ $\xrightarrow[NaNO_2 / HCl]{} X$ $\xrightarrow{H_2O} Y$ $\xrightarrow{Cu / 573 \ K} Z$
$I$. $Z$ is an aldehyde
$II$. $Z$ undergoes Cannizzaro reaction
$III$. $Z$ gives iodoform test
$IV$. $Z$ does not give test with Tollens' reagent

The total number of structural products formed in the following reaction sequence is $CH_3COCl \xrightarrow{i) (CH_3)_2Cd} (P)$; $(P) + CH_3CHO \xrightarrow{ii) NaOH (aq.), \Delta} ?$

$CH_3CHO$ $\xrightarrow{HCN} A$ $\xrightarrow{H_3O^+} B$. The product $B$ is

What is the reaction of benzaldehyde with aniline called?