Question

Which of the following is a Lewis base?

• A. $BC{l}_3$
• B. $C_2{H}_2$
• C. $HCl$
• D. $A{g}^{+}$

Answer 1

Answer: (B)

$C_2{H}_2$

Carbon molecules which have pie electrons i.e multiple bonds of a carbon have more electron density in that bond which can be easily donated to other species so they generally act as lewis base. While other molecules like $BC{l}_3$, HCl and $A{g}^{+}$ are have less electron density in their molecules so they cannot donate pair of electrons hence they are not Lewis base.