Which of the following compounds is reduced to the corresponding hydrocarbon by $Zn-Hg$ and concentrated $HCl$?

Why is there a large difference in the boiling points of butanal and butan$-1-$ol?

After completion of the reactions $(I)$ and $(II)$,the organic compound$(s)$ in the reaction mixtures is (are):

Which of the following reagents can form a hydrazone with alkanone?

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

Amongst the following compounds, the one that will not respond to Cannizzaro reaction upon treatment with alkali is