Which of the following compounds does not undergo haloform reaction?

What will be the order of reactivity of the following carbonyl compounds with a nucleophile?
$(I)$ $HCHO$
$(II)$ $CH_3CHO$
$(III)$ $(CH_3)_2CO$
$(IV)$ $(Me_3C)_2CO$

Benzaldehyde and acetone can be best distinguished using

The major products in the reaction $Br_3CCHO \stackrel{NaOH}{\longrightarrow}$ are $....$

Predict the major product of the following reaction:
$1,3$-benzodioxole $\xrightarrow[(ii) CHCl_3, NaOH]{(i) HI \text{ (excess)}}$ ?

The reaction of $50\%$ aq $KOH$ on an equimolar mixture of $4-$methylbenzaldehyde and formaldehyde followed by acidification gives