Question:
Which of the following compound CANNOT act as a Lewis base?
Correct Option: , 2
Solution:
Lewis base : Chemical species which has
capability to donate electron
pair.
In $\mathrm{NF}_{3}, \mathrm{SF}_{4}, \mathrm{ClF}_{3}$ central atom (i.e. $\mathrm{N}, \mathrm{S}, \mathrm{Cl}$ ) having lone pair therefore act as lewis base.
In $\mathrm{PCl}_{5}$ central atom $(\mathrm{P})$ does not have lone pair therefore does not act as lewis base.