How is #H^+# acting in the reaction #H^++:NH_3 ->[H:NH_3]^+#according to the Lewis definition?

1 Answer
Oct 25, 2014

H⁺ is acting as a Lewis acid.

A Lewis acid is an electron pair acceptor.

H⁺ ←:NH₃ → NH₄⁺

The Lewis base NH₃ has donated its electron pair to form an N-H bond, and the Lewis acid H⁺ has accepted them.

One-half of the shared electrons in the N-H bond now belongs to the H atom.

You can tell that H⁺ has accepted electrons by counting the formal charges.

Before the reaction, the formal charge on H⁺ is +1. After the reaction, the H has a formal charge of 0.

The H atom has formally gained an electron, so it is an electron acceptor, a Lewis acid.