# How would you distinguish between a Lewis acid and a Lewis base?

Well, which is the $\text{electron pair donor}$....? And this is conceived to be the $\text{Lewis-base}$, and the $\text{electron pair acceptor}$ is conceived as the $\text{Lewis acid}$...
And typical $\text{Lewis acids}$ are $B {X}_{3}$, ${B}_{2} {H}_{6}$, and ""^(-)C-=O^(+)...and $\text{Lewis bases}$ are $H {O}^{-}$, $A l {X}_{3}$, and $P {R}_{3}$, and $N {H}_{3}$...