$30 \mathrm{g}$ of a monobasic carboxylic acid $\mathrm{A}$ consumed $0.5 \mathrm{moles}$ of $\mathrm{NaOH}$ for its neutralisation. $\mathrm{A}$ is subjected to the following treatments:

$\left[\mathrm{A}\right]\stackrel{{\mathrm{Cl}}_2/\mathrm{P}}{\to }\left(\begin{array}{l}\text{ Monochloro }\\ \text{ derivative }\end{array}\right)\underset{\mathrm{with} {\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}}{\overset{\mathrm{Esterification}}{\to }}\left(\mathrm{Ester}\right)\stackrel{\mathrm{KCN} \mathrm{alc}}{\to }\left[\mathrm{B}\right]\underset{\mathrm{Acid}}{\overset{\mathrm{Hydrolysis}}{\to }}\mathrm{Dicarboxylic} \mathrm{acid}\left[\mathrm{C}\right]\underset{150°\mathrm{C}}{\overset{\mathrm{Heat}}{\to }}\mathrm{A}$

Give the structures of $\mathrm{A},\mathrm{B},\mathrm{C}$ by providing the sequence of reactions.

In the reaction sequence,

$\stackrel{\mathrm{Y}}{⟶}{\mathrm{CH}}_3\mathrm{C}\equiv \mathrm{N}\stackrel{\mathrm{Z}}{⟶}{\mathrm{CH}}_3{\mathrm{COOC}}_2{\mathrm{H}}_5$

what is $\mathrm{X},\mathrm{Y} \text{and} \mathrm{Z}$?

Pick up the major product in the following reaction.

Sodium malonate having one labeled oxygen is decarboxylated to form monocarboxylic acid. Predict the final products.

$\mathrm{HOOC}-{\mathrm{CH}}_2-{\mathrm{COO}}^{18}\mathrm{H}\stackrel{1.\mathrm{NaOH}}{⟶}$

$\mathrm{HOOC}-{\mathrm{CH}}_2{{\mathrm{COO}}^{18}}^{-}{\mathrm{Na}}^{+}\stackrel{\text{ heat }}{⟶}$

Identify the product $\mathrm{Z}$ in the following series of reactions.

$\mathrm{HOOC}-{\left({\mathrm{CH}}_2\right)}_2-\mathrm{COOH}$ $\stackrel{\mathrm{P}/{\mathrm{Br}}_2}{⟶}\mathrm{X}\stackrel{\text{ alc. KOH }}{⟶}\mathrm{Y}\stackrel{∆}{⟶}\mathrm{Z}$

HVZ reaction involves the use of $\mathrm{P}$ and ${\mathrm{Cl}}_2$

${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{COOH}\stackrel{\mathrm{P},{\mathrm{Cl}}_2}{⟶}{\mathrm{CH}}_3\mathrm{CHClCOOH}$

The function of phosphorus is

Salicylic acid is treated with bromine under two different conditions.

Predict the nature of $\left[\mathrm{X}\right]$ and $\left[\mathrm{Y}\right]$ in the above reactions.