Question

How do you identify Bronsted-Lowry acids and bases?

Answer 1

Hint: To solve this we must know that any species that donates a proton i.e. \[{{\text{H}}^ + }\] ion is known as a Bronsted-Lowry acid. And any species that accepts a proton i.e. \[{{\text{H}}^ + }\] ion is known as a Bronsted-Lowry acid. Thus, Bronsted-Lowry acids are proton donors and Bronsted-Lowry bases are proton acceptors.

Complete solution:
We know that any species that donates a proton i.e. \[{{\text{H}}^ + }\] ion is known as a Bronsted-Lowry acid. And any species that accepts a proton i.e. \[{{\text{H}}^ + }\] ion is known as a Bronsted-Lowry acid.
Thus, Bronsted-Lowry acids are proton donors and Bronsted-Lowry bases are proton acceptors.
For example consider the reaction of hydrochloric acid and water. Hydrochloric acid reacts with water and produces a chloride ion i.e. ${\text{C}}{{\text{l}}^ - }$ ion and a hydronium ion i.e. ${{\text{H}}_{\text{3}}}{{\text{O}}^ + }$ ion. The reaction of hydrochloric acid with water is as follows:
${\text{HCl}} + {{\text{H}}_{\text{2}}}{\text{O}} \to {\text{C}}{{\text{l}}^ - } + {{\text{H}}_{\text{3}}}{{\text{O}}^ + }$
In the above reaction, we can see that hydrochloric acid i.e. ${\text{HCl}}$ donates a proton and water i.e. ${{\text{H}}_{\text{2}}}{\text{O}}$ accepts a proton.
Thus, we can say that ${\text{HCl}}$ is a Bronsted-Lowry acid because it donates a proton and ${{\text{H}}_{\text{2}}}{\text{O}}$ is a Bronsted-Lowry base because it accepts a proton.
Thus, we can identify Bronsted-Lowry acids by the proton donating species and Bronsted-Lowry bases by the proton accepting species.

Note: Hydrochloric acid reacts with water and produces a chloride ion i.e. ${\text{C}}{{\text{l}}^ - }$ ion and a hydronium ion i.e. ${{\text{H}}_{\text{3}}}{{\text{O}}^ + }$ ion. The species that can gain a proton and form an acid is known as a conjugate base. Thus, ${\text{C}}{{\text{l}}^ - }$ ion is a conjugate base. The species that can donate a proton and form a base is known as a conjugate acid. Thus, ${{\text{H}}_{\text{3}}}{{\text{O}}^ + }$ ion is a conjugate acid.