Question

Is ${\mathrm{NH}}_3$ a Lewis acid or base?

Answer 1

According to Lewis, a base is a substance that can donate a lone pair of electrons and acid is a substance that can accept lone pair of electrons.

Ammonia$\mathbf{\left(}{\mathbf{NH}}_{\mathbf{3}}\mathbf{\right)}$ is a base because it has a lone pair of electrons and can donate to an electron-deficient compound.

Hence, ammonia $\mathbf{\left(}{\mathbf{NH}}_{\mathbf{3}}\mathbf{\right)}$ is a lewis base.