43.

Which of the following statements about primary amines is false?

• Alkyl amine are stronger bases than aryl amines

• Alkyl amines reacts with nitrous acid to produce alcohols

• Aryl amines react with nitrous acid to produce phenols

• Alkyl amines are stronger base than ammonia

i) The presence of electron withdrawing substituent decrease the basicity while the presence of electron releasing substituent like, -CH₃ - C₂H₅ etc increases the acidity.

ii) HNO₂ converts - NH₂ group of an aliphatic amine into - OH while that of aromatic amines into - N =NCl.

Since phneyl group is a electron withdrawing group, it decreases the basicity. Alkyl group, on the other hand, being electron releasing, increases the basicity. Thus, alkyl amines are more basic as compared to arylamines as well as ammonia.

$\mathrm{R}-{\mathrm{NH}}_2 \stackrel{{\mathrm{HNO}}_2}{\to } \mathrm{R} -\mathrm{OH}$
Thus, HNO₂ (nitrous acid ) converts alkyl amines to alcohols. But,

${\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{NH}}_2 \stackrel{{\mathrm{HNO}}_2}{\to } \underset{\mathrm{benzene} \mathrm{diazonium} \mathrm{chloride}}{{\mathrm{C}}_6{\mathrm{H}}_5\mathrm{N} = \mathrm{NCl}}$

Thus, HNO₂ does not convert aryl amines into phenol.