What is a conjugate acid or base?

[MHarrold_1E]

What exactly is a conjugate acid or base? Do all acids have a conjugate base?

[Ria Nawathe 1C]

A conjugate acid is the resulting species when a base accepts a proton, and a conjugate base is the species that results when an acid gives off a proton.

For example, the conjugate acid of the base NH3 is NH4+, as NH3 + H+ --> NH4+. The conjugate base of H2SO4 is HSO4-, since H2SO4 donating a proton leaves the anion HSO4-.

Hope this helps!

[Hannah Alltucker 3L]

A conjugate base is what remains after the acid has given up a proton (So the acid - one H+). A conjugate acid is the base once it has gained that proton (so the base + one H+). Because acid/base reactions also have the ability to go in the reverse direction, I like to think of the conjugates as what would act as the acid and base in a reverse reaction.

Another good thing to remember is that the strength of an acid can be considered as how well that acid remains its conjugate base, a strong base can be considered as how well a base remains its conjugate acid!

All acids and bases will have a conjugate!

[Alara Aygen 3K]

If you are given a base and asked to find the conjugate acid, you need to add one H atom since Bronsted bases are proton acceptors.
If you are given an acid and asked to find the conjugate base, you need to remove one H atom, since the Bronsted acids are proton donors.

[jessicasilverstein1F]

These can be confusing to me. I think of it like this:
A conjugate acid is the resulting formula when a base accepts a proton (H+), and a conjugate base is the species that results when an acid gives off a proton (H+).

[Vanshika Bhushan 1A]

A conjugate acid contains one more H atom and one more + charge than the base that formed it. A conjugate base contains one less H atom and one more - charge than the acid that formed it. All acids and bases have conjugate bases.

[805401611]

A conjugate acid contains one more H atom and one more + charge when formed a base while a conjugate base contains one less H atom and one more - charge when formed from an acid. Also, all acids have a conjugate base (they just simply differ in strength, depending on the strength of the acid)! Hope that helps!

[Acharya Ranawat 3E]

A conjugate acid is what is formed when you protonate the base in the reactant side of the equation. A conjugate base is what is formed when you deprotonate an acid on the reactant side. Keep in mind conjugate refers to the product side of the equation. Hope this helps!

[Anubhav_Chandla1G]

A conjugate base or acid is what is left of a compound after an acid or base is formed. In other words, when a base accepts a proton, that is now a conjugate acid, and when an acid donates a proton, the species that is left is now the conjugate base.

[Eric Sun 2G]

A conjugate base/acid is what is the product formed when an acid/base donates or accepts a proton. When an acid gives up a proton, the resulting product would be a conjugate base as that compound can now reaccept a proton to become an acid again. When a base accepts a proton, the resulting product would be a conjugate acid as that compound can now donate a proton to become a base again.

[Karen Harrison 1L]

This was confusing to me too, until I looked up the definition of conjugate.
Conjugate, in chemistry, means the reverse reaction of something. So when looking at Bronsted acids and Bronsted bases, the conjugate of a Bronsted acid would be a conjugate base because it is the one that can accept a proton with the reverse of the reaction. This is the same thing with a conjugate of a Bronsted base--it would be a conjugate acid because it can donate a proton with the reversal of the reaction. For example, the forward reaction of HCl- and H2O is Cl- and H3O+. The Bronsted acid is HCl- because is going to donate the hydrogen ion when water is added. The conjugate base is Cl- because in the reverse of the reaction, it can accept back the hydrogen ion. This can be done for H2O. We know that H2O is a Bronsted base because it is accepting a proton in the forward reaction, but then donating the proton in the backwards reaction, making H3O+ the conjugate acid.
Try not to confuse the these definitions of Lewis acids and Lewis bases, which describe which atoms can donate or accept a pair of electrons. (ie. Cl- is a Lewis base because it can donate an electron and H3O+ is a Lewis acid because it can accept a pair of electrons).

[Rebecca Preusch 2C]

A conjugate acid is formed by adding a hydrogen ion to a base, and will act as the acid in the reverse reaction. A conjugate base is created from the forward reaction's acid and will act as the base in the reverse reaction. Strong acids have weak conjugate bases and vice versa. Every base has a conjugate acid and every acid has a conjugate base.

[Jessica Servoss 1H]

Conjugate acids are formed when a proton (H+) is added to a base, which allows the molecule to now act as an acid. For conjugate bases, a proton (H+) is removed, allowing the molecule to act as a base. For example, if we have HSO4- and H2O, the hydrogen on the SO4- becomes joined to the H2O, forming H3O+ (the conjugate acid since the H+ was added to it) and SO4-2 (the conjugate base since the H+ was removed from the molecule).

[Jiayin Yola Yan 1G]

Conjugate acid is after the original species (the base) donates a proton, and can be written as the base + proton. Conjugate base of an acid can be written as the acid - proton.