(i) Chemical name of the poisonous vapours is methyl isocynate(MIC)
(ii) It can be prepared by heating methyl amine and phosgene.
(iii) The compound is highly reactive towards group like hydroxyl,amino, thio etc  which are present in enzymes , proteins , carbohydrates , cellular fluids like water present in human system. It destroys the lung tissues and causes acute breathing problems It is also absorbed by the skin and causes its destruction.
(iv) The factories where such chemicals are produced must be installed away from the cities and villages, preferably in remote areas. Proper training must be given to the factories and inspections must be carried out from time to time to ensure that everything is in order.

 

(b) C₂H₅NH₂ < (C₂H₅)₃N < (C₂H₅)₂NH
(c) Add CHCl₃ and alc. KOH, C₆H₅-NH₂ gives foul smell of isocyanide whereas C₆H₅-NH-CH₃ does not (or any other correct test).

(ii) Alcohols have higher boiling point as compared to that of amines, because oxygen being more electronegative atom, forms strong hydrogen bond as compared to that of nitrogen. In tertiary amine, there is no hydrogen bond formation due to the absence of H-atoms and hence, has the lowest boiling point. Therefore, increasing order of boiling point (CH₃)₃N < C₂H₅NH₂ < C₂H₅OH .
(iii) (CH₃)₃NH and (CH₃)₃N are secondary and tertiary arnines respectively. These are distinguished by Hinsberg's reagent which gives sulphonamide with secondary amines and no reaction carried out with tertiary arnines. (CH₃)₃NH reacts with benzene sulphonyl chloride as follows:

The amide has the following resonating structures:
  
Due to the delocalisation of lone pair of electrons on N over C==O group, amino group acquires a positive charge which ma, es N-H bond weak. Moreover, the anion formed after removal of a proton is also stabilized by resonance as :
  
However, no such stabilization is possible in amines.

Due to strong electron-donating effect of the -NH₂  group, the electron density increases at the 0-, positions. Further, when aniline is treated with Br₂ the Br⁺ attacks the benzene ring at o- and p-positions to form carbocation intermediates which are stabilized not only by the usual resonance of the Henzene ring. but also by the -NH₂ group as shown below: In case of o-bromination, the carbocation intermediate is stabilized not only by usual resonating structure (I, III and IV) but is also stabilized by resonance structure (II) in which the lone pair of electrons on the N. atom interacts with the positively charged carbon of the ring. Similarly, in case of p-bromination, the carbocation is stabilized not only by the usual resonating structures (V, VI, and VIII) but is also stabilized by the resonance structure (VII) in which the lone pair of electrons on the N-atom interacts with the positively charged carbon of the ring. These additional resonating structures (II and VII) increase the stability of the carbocation to such an extent that bromination occurs instantaneously at the p- and two. o- positions giving 2, 4, 6-tribromoaniline.