Which one of the following on oxidation will not give a carboxylic acid with the same number of carbon atoms?

Match the compounds/ions in Column $I$ with their properties/reactions in Column $II$.

Column $I$	Column $II$
$A$. $C_6H_5CHO$	$p$. gives precipitate with $2, 4-$dinitrophenylhydrazine
$B$. $CH_3C \equiv CH$	$q$. gives precipitate with $AgNO_3$
$C$. $CN^{-}$	$r$. is a nucleophile
$D$. $I^{-}$	$s$. is involved in cyanohydrin formation

When cyclohexanone reacts with dimethylamine in the presence of a catalytic amount of acid,water is continuously removed during the reaction. What is the product commonly called?

The following transformation can be best carried out using:

Which of the following substances will not give a yellow precipitate with $I_2/NaOH$?

The best reagent to carry out the following conversion is:
$3$-hydroxyethylcyclopentane-$1$-carbaldehyde $\rightarrow$ $1$-ethyl-$3$-methylcyclopentane (with a hydroxy group on the ethyl side chain).
(Note: The image shows the reduction of an aldehyde group $-CHO$ to a methyl group $-CH_3$ while keeping the secondary alcohol $-CH(OH)CH_3$ intact.)