Question

Which of the following cannot act as Bronsted-Lowry base?

• A. $O{H}^{-}$
• B. $N{H}_4^{+}$
• C. $S{H}^{-}$
• D. All three act as a Bronsted-Lowry base

Answer 1

The correct option is B $N{H}_4^{+}$

A Bronsted-Lowry base is any species that can accept a proton from another molecule.
(a), (c) both can accept proton $H^{+}$ to form $H_{2}O,H_{2}S$ respectively.
In (b), nitrogen is in its maximum valency state and cannot accept $H^{+}$, so it cannot act as Bronsted Lowry base.