Question

Which of the following molecule can combine with a proton $\left(H^{+}\right)$?

• A. $N{H}_3$
• B. $N{a}^{+}$
• C. $HCl$
• D. $H_3{O}^{+}$
• E. $H$

Answer 1

The correct option is A $N{H}_3$

The molecules already having positive charge $(N{a}^{+}$ and $H_3{O}^{+})$ means that they are electron deficient and they can not combine with another proton $\left(H^{+}\right)$. $HCl$ is an acid, that releases a proton. Ammonia $N{H}_3$ acts as a base because, the unshared pair of electrons in the ammonia molecule can combine with a proton, forming the ammonium $\left(N{H}_4^{+}\right)$ ion.