Which of the following chemicals are responsible for the production of methyl isocyanate,which caused the Bhopal gas tragedy?

How will you convert:
$(i)$ Ethanoic acid into methanamine
$(ii)$ Hexanenitrile into $1$-aminopentane
$(iii)$ Methanol to ethanoic acid
$(iv)$ Ethanamine into methanamine
$(v)$ Ethanoic acid into propanoic acid
$(vi)$ Methanamine into ethanamine
$(vii)$ Nitromethane into dimethylamine
$(viii)$ Propanoic acid into ethanoic acid?

An organic compound $A$ reacts with $NH_3$ on heating to give $B$. Compound $B$ reacts with $Br_2$ in the presence of $KOH$ to give $CH_3CH_2NH_2$. What is $A$?

In the given reaction,the end product $(C)$ is:

Given below are some nitrogen-containing compounds. Each of them is treated with $HCl$ separately. $1.0 \ g$ of the most basic compound will consume $........$ $mg$ of $HCl$. ($Given$ molar mass in $g \ mol^{-1}$: $C:12, H:1, O:16, Cl:35.5$)

In the given reaction,$A$ is:
$A$ $\xrightarrow{\text{Reduction}} B$ $\xrightarrow{HNO_2} C_2H_5OH$