Identify the Lewis acids and bases in the following reactions and write the products.
a)
O
||
C + AlCl3 -->
/ \
H3C CH3
b)
H
N + BF3 -->
/ \
H3C CH3
In order to identify the Lewis acids and bases in the given reactions and write the products, we need to understand the concept of Lewis acids and bases.
A Lewis acid is a chemical species that can accept a pair of electrons (also known as an electron pair acceptor), while a Lewis base is a chemical species that can donate a pair of electrons (also known as an electron pair donor).
a) In the reaction given:
O
||
C + AlCl3 -->
/ \
H3C CH3
The AlCl3 molecule is a Lewis acid, as it can accept a pair of electrons. The C=O portion of the molecule acts as a Lewis base, as it can donate a pair of electrons to the AlCl3. When the AlCl3 accepts the electron pair from the C=O, it forms a coordinate bond. The product of the reaction is the formation of a bond between AlCl3 and the C=O portion of the molecule, resulting in the formation of a Lewis acid-base adduct.
b) In the reaction given:
H
N + BF3 -->
/ \
H3C CH3
The BF3 molecule is a Lewis acid, as it can accept a pair of electrons. The lone pair of electrons on the nitrogen (N) atom in the HNCH3 molecule acts as a Lewis base, as it can donate a pair of electrons to the BF3. When the BF3 accepts the electron pair from the nitrogen, it forms a coordinate bond. The product of the reaction is the formation of a bond between BF3 and the nitrogen atom, resulting in the formation of a Lewis acid-base adduct.
To summarize:
a) Lewis acid: AlCl3
Lewis base: C=O
Product: Lewis acid-base adduct (AlCl3-C=O)
b) Lewis acid: BF3
Lewis base: Nitrogen (N)
Product: Lewis acid-base adduct (BF3-N)