Question #c729d

As you know, a Bronsted-Lowry acid is characterized by the fact that it can act as a proton donor. Likewise, a Bronsted-Lowry base is characterized by the fact that it can accept a proton.

A proton, `"H"^(+)`, is simply the nucleus of a hydrogen atom, `"H"`.

In a given chemical reaction, you can identify a Bronsted-Lowry acid by looking for the chemical species that loses a proton. Consequently, the chemical species that accepts the proton lost by a Bronsted-Lowry acid will act as a Bronsted-Lowry base.

Now, the chemical species that is left behind after an acid donates a proton is called a conjugate base because it can accept a proton to reform the original acid.

Likewise, the chemical species that is formed when a base accepts a proton is called a conjugate acid because it can donate this proton to reform the original base.

In your case, you have

`color(red)("H")"NO"_ (3(aq)) + "SO"_ (4(aq))^(2-) -> color(red)("H")"SO"_ (4(aq))^(-) + "NO"_(3(aq))^(-)`

Here `"HNO"_3` donates its proton to `"SO"_4^(2-)`, which accepts it to form `"HSO"_4^(-)`.

As a result, you can say that `"HNO"_3` acts as an acid and `"SO"_4^(2-)` acts as a base.

`overbrace(color(red)("H")"NO"_ (3(aq)))^(color(purple)("acid")) + overbrace("SO"_ (4(aq))^(2-))^(color(green)("base")) -> color(red)("H")"SO"_ (4(aq))^(-) + "NO"_(3(aq))^(-)`

Now, `"HNO"_3`, which is called nitric acid, donates its proton to leave behind the nitrate anion, `"NO"_3^(-)`, which means that the nitrate anion will be the acid's conjugate base.

On the other hand, `"SO"_4^(2-)`, which is the sulfate anion, accepts a proton to form `"HSO"_4^(-)`, the hydrogen sulfate anion, which means that the hydrogen sulfate anion is the base's conjugate acid.

`overbrace(color(red)("H")"NO"_ (3(aq)))^(color(purple)("acid")) + overbrace("SO"_ (4(aq))^(2-))^(color(green)("base")) -> overbrace(color(red)("H")"SO"_ (4(aq))^(-))^(color(green)("conjugate acid")) + overbrace("NO"_(3(aq))^(-))^(color(purple)("conjugate base"))`