For the reaction C5H5N(aq) + H2O(l) C5H5NH+(aq) + OH-(aq), which of the following is a conjugate acid-base pair?

a. C5H5N, C5H5NH+
b. C5H5NH+, OH-
c. H2O, OH-
d. C5H5N, H2O

Respuesta :

A conjugate acid results when a chemical species receives a hydrogen ion. Moreover, the conjugate base is what is formed after the conjugate acid has been formed. In this case, C5H5N accepts a hydrogen ion, becoming a conjugate acid and the species left over is OH-, making it the conjugate base. Therefore, the answer is B.

Answer: b. [tex]C_5H_5NH^+[/tex], [tex]OH^-[/tex]

Explanation:

According to the Bronsted-Lowry conjugate acid-base theory, an acid is defined as a substance which looses donates protons and thus forming conjugate base and a base is defined as a substance which accepts protons and thus forming conjugate acid.

For the given chemical equation:

[tex]C_5H_5N(aq.)+H_2O(l)\rightarrow C_5H_5NH^+(aq.)+OH^-(aq.)[/tex]

Here, [tex]C_5H_5N[/tex] is accepting a proton, thus it is considered as a base and after accepting a proton, it forms [tex]C_5H_5NH^+[/tex] which is a conjugate acid.

And, [tex]H_2O[/tex] is losing a proton, thus it is considered as an acid and after loosing a proton, it forms [tex]OH^-[/tex] which is a conjugate base.

Hence, the correct answer is b. [tex]C_5H_5NH^+[/tex], [tex]OH^-[/tex]