Question

Given the reaction:

HCl(g) + H2O(l) → H3O+(aq) + Cl−(aq)
Which reactant acted as a Bronsted-Lowry acid?
A) H2O(l), because it accepted protons
B) H2O(l), because it produced hydronium ions C) HCl(g), because it donated protons
D) HCl(g), because it reacted with chloride ions

Answer 1

The correct answer is option C.

Step-by-step 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.
• A base is defined as a substance which accepts protons and thus forming conjugate acid.

For the given chemical equation:

`HCl(g) + H_2O(l) \rightarrow H_3O^+(aq) + Cl^-(aq)`

Here,
`HCl` is loosing a proton, thus it is considered as an acid and after losing a proton, it forms
`Cl^-` which is a conjugate base.

And,
`H_2O` is gaining a proton, thus it is considered as a base and after gaining a proton, it forms
`H_3O^+` which is a conjugate acid.

Hence,the correct answer is option C.