Is $Be{{H}_{2}}$ a Lewis acid?

Hint:Lewis acid means, the acid should have a capability to accept electrons from others then it is called a Lewis acid. To accommodate the extra electrons the Lewis acid should have vacant orbitals in its structure.

Complete step-by-step answer:- In the question it is asked whether beryllium hydride is going to act as a Lewis acid or not.
- Beryllium is an element belonging to s block.
- The atomic number of Beryllium is 4.
- Means beryllium has a total number of four electrons in it.
- The electronic configuration of beryllium is $1{{s}^{2}}2{{s}^{2}}$ .
- Therefore beryllium forms two bonds with two hydrogen atoms and forms a molecule of beryllium hydride.
- Beryllium hydride is linear in shape.
- In beryllium hydride there are 4 electrons in the outer shell, to form an octet beryllium should accept 4 electrons from others.
- Because of the reason to get octet beryllium hydride is going to accept electrons and make them to fill in the vacant orbitals to get octet configuration.
- Therefore beryllium hydride is going to accept electrons from others to get octet configuration.
- So, beryllium hydride is a Lewis acid.

Note:Few molecules get octet configuration after accepting electrons from others and exhibit octet electronic configuration and show stability. In the process to exhibit octet configuration the molecules are going to act as Lewis acids.
Lewis bases are the molecules they exhibit octet configuration after donating extra electrons with it.