An important reaction of acetone is autocondensation in the presence of concentrated sulphuric acid to give the aromatic compound:

Cyanohydrin of which of the following forms lactic acid?

Upon treatment with $Al(OEt)_3$ followed by usual reactions (work up), $CH_3CHO$ will produce

Draw structures of the following derivatives:
$(i)$ The $2,4-$dinitrophenylhydrazone of benzaldehyde
$(ii)$ Cyclopropanone oxime
$(iii)$ Acetaldehyde dimethyl acetal
$(iv)$ The semicarbazone of cyclobutanone
$(v)$ The ethylene ketal of hexan$-3-$one
$(vi)$ The methyl hemiacetal of formaldehyde

$X \underset{\text{Reductive}}{\stackrel{\text{Ozonolysis}}{\longrightarrow}} Y + Z$. $Y$ can be obtained by Etard's reaction,$Z$ undergoes disproportionation reaction with concentrated alkali. $X$ could be:

Which is not true about acetophenone?