The conversion of $CH_{3}CH_{2}COOH$ to the product shown below can be accomplished by:
$CH_{3}CH_{2}CH(OCH_{2}CH_{2}O)$

$CH_3-CO-CH_2-CH_2-CH_2-CO_2H \xrightarrow[(ii) H_2O, H^+]{(i) NaBH_4} ?$
What will be the final product of this transformation?

The major product in the following reaction is

Calculate the value of $x + \text{molecular mass of } (C)$,where $x$ is the number of moles of $PhMgBr$ consumed in reaction $(a)$ and $(C)$ is the gas evolved in reaction $(b)$.
$(a)$ $3\text{-hydroxy-5-formylbenzoyl chloride} + x \ PhMgBr \xrightarrow{\text{excess}} (A)$
$(b)$ $2,5\text{-dioxocyclohexanecarboxylic acid} \xrightarrow{\Delta} (B) + (C) \uparrow$

Arrange the following compounds in the increasing order of their $pK_a$ values:
$I.$ Phenol
$II.$ $p$-Nitrophenol
$III.$ Ethanol
$IV.$ $p$-Nitrobenzoic acid

Which of the following best describes the nucleophilic addition step in the acid-catalyzed hydrolysis of acetonitrile $(CH_3CN)$?