Short Answer TypeExplain how does the presence or absence of hydrogen on N of amines affect the modes of their reactions with nitrous acid?
Arrange the isomeric compounds:
(i) Ethyldimethyl amine
(ii) n-butyl amine
(iii) diethyl amine
in order of decreasing boiling point and give reason.
Explain the following general order of basicity in aqueous solution:
R2NH > RNH2 > R3N > NH3
Two effects: inductive and the solvation effect determines the basicity of alkyl amines.
As the number of alkyl group (electron releasing group with +I effect) increases, making the amine more basic. So, in terms of inductive effect, increasing the number of R's should increase the basicity.
Solvation is present only in the conjugate acid, more the number of H present in the conjugate acid more the H-bonding and more the stabilisation. Therefore the R' increases, the number of H-s in the conjugate acid decreases, solvation decreases. Hence, basicity should decrease.
The inductive and solvation effect both works in opposite direction. Inductive effect dominates to make all three amines stronger bases than NH3.
While in R3N solvation effect dominates over the inductive effect.
Explain the following general order of basicity in aqueous solution:
R3N ,R2NH , RNH2
What will be the basic strength order of these amines in gas phase?
How can you find out whether a given amine is a primary amine? Write the chemical reaction involved in the test you perform.
Long Answer TypeHow can you separate a mixture of primary, secondary and tertiary amines? Write chemical reactions involved in the process.
Switch
