Write the structure of the product of the following reaction.

What is the name of the reaction: ${C_6}{H_5}CONH_2 \xrightarrow{PCl_5} C_6H_5CN$?

Identify the structure of product $A$ in the following reaction:
$\text{Cyclohexanecarboxylic acid} \xrightarrow{LiAlH_4} A$

The descending order of acidity for the following carboxylic acids is:
$A.$ $CH_3COOH$
$B.$ $F_3C-COOH$
$C.$ $ClCH_2-COOH$
$D.$ $FCH_2-COOH$
$E.$ $BrCH_2-COOH$
Choose the correct answer from the options given below:

In the following sequence of reaction,$CH_3Br$ $\xrightarrow{KCN} (A)$ $\xrightarrow{H_3O^{+}} (B)$ $\xrightarrow{LiAlH_4, \text{ ether}} (C)$. The end product $(C)$ is

An acid $X$ is neutralized with $NaOH$ and the salt produced is fused with sodalime,resulting in the production of isobutane. $X$ can be: