Answer:
This question is incomplete because of the absence of the molecules been referred to in the question. However, the molecules been referred to in the question is in the attachment below
Explanation:
First of all, we have to define lewis acid and lewis base.
A lewis acid is a substance that has the capacity to accept a pair of electrons. For example, H⁺. While a lewis base is a substance that is capable of donating a pair of electrons (to a lewis acid). For example, OH⁻.
Going by the definitions above, we can deduce the type of substance the molecules in the question (attachment) are
a. BF₃ (boron trifluoride) is a lewis acid because the central atom (as suggested to be focused on in the question) which is <u>boron, has the capacity to accept a pair of electrons</u>.
b. The central atom (carbon) in the compound (2-methyl propane) <u>also has the capacity to accept a pair of electrons</u> since it is positively charged (is electron deficient). Hence, it is a lewis acid.
c. The functional group in this compound (trimethyl borate) is the ether. Ethers are generally lewis bases because the oxygen atom in an ether can donate a pair of electrons from it's lone pair. However, the <u>presence of boron which is central to the compound</u> shows it is also a lewis acid, although weak (majorly due to the presence of the ethers).
