Question

Which of the following molecule/ion has highest potential to act as a Lewis acid?

• A. ${}^{+}C{H}_3$
• B. ${}^{-}CN$
• C. $N{H}_3$
• D. $B{F}_4^{-}$
• E. $C{O}_2$

Answer 1

The correct option is A ${}^{+}C{H}_3$

Due to being positively charged and having one electron pair less, from the complete octet , $+C{H}_3$ can act as Lewis acid.
In the Lewis theory of acid-base reactions, bases donate pairs of electrons and acids accept pairs of electrons. A Lewis acid is therefore any substance, such as the $H^{+}$ ion, that can accept a pair of nonbonding electrons. In other words, a Lewis acid is an electron-pair acceptor. A Lewis base is any substance, such as the $O{H}^{-}$ ion, that can donate a pair of nonbonding electrons. A Lewis base is therefore an electron-pair donor.