Question

In the Ammonia-Boron trifluoride complex, the donor molecule is Ammonia.
(a) True
(b) False

Answer 1

Hint: In the Ammonia-Boron trifluoride complex, one part will act as Lewis Acid and the other will act as Lewis base. So, the Lewis Acid will accept the electrons and the Lewis Base will donate the electrons.

Complete Solution :
> The compounds are formed when the electrons between the atoms are either shared between the atoms or donated from one atom or molecule to the other. When the compound or complex is formed when there is a donation of electrons from one atom or molecule to the other either an ionic bond or coordinate bond is formed. Then there will be two parts: Lewis Acid and Lewis Base.
> In the Ammonia-Boron trifluoride complex, one part will act as Lewis Acid and the other will act as Lewis base. So, the Lewis Acid will accept the electrons and the Lewis Base will donate the electrons.
> The formula of Ammonia-Boron trifluoride is ${{H}_{3}}N\to B{{F}_{3}}$, and its structure is given below:

> So, in Ammonia-Boron trifluoride, ammonia is one part and the boron trifluoride is the other part. In ammonia, there is a lone pair on the nitrogen atom which is available for donation, and in boron trifluoride, the boron atom has a deficiency of two electrons to complete its octet. Therefore, ammonia is the Lewis Base because of the donation of electrons, and Boron trifluoride is the Lewis Acid because it accepts a pair of electrons.

So, the given statement “In Ammonia-Boron trifluoride complex, the donor molecule is Ammonia” is true.

Note: Some other examples of Lewis Acid are aluminium trichloride ($AlC{{l}_{3}}$), ferric chloride ($FeC{{l}_{3}}$), and some other examples of Lewis Base are $R-N{{H}_{2}}$, $R-OH$, $H-O-H$, etc. When an acid or a base combines only coordinate or dative bonds are formed.