Question

Arrange the following compounds in decreasing order of basic strength ( In gaseous phase):
${NH}_3$, ${\left({C_{2}H}_5\right)}_{2}NH$, ${\left({CH}_3\right)}_{3}N$.

Answer 1

The basicity order of the following compounds is:

${(CH}_3)N_3>{\left(C_2{H}_5\right)}_2-NH>{NH}_3$

In case of $3^0$ amine $+I$ effect of three methyl group attached to the nitrogen which increases the electron density on nitrogen atom.

On the other hand $+I$ effect of two ethyl group attached to the nitrogen atom which develops the electron density on nitrogen.

In case of ammonia,it is basic in nature but there is no effect $+I$ effect of alkyl group.