NOTE ON CONJUGATE ACIDS-BASES AND BASICITY.

CONJUGATE ACID AND CONJUGATE BASE.

*Now, let us take a look at CONJUGATE ACIDS and CONJUGATE BASES*

First, let’s us know what Β *conjugate of an acid* means and what *conjugate of a base means.

*When one hydrogen atom is removed from an acid, whatever that remains in the acid is known as the CONJUGATE base of that acid*

Also

*When one hydrogen is added to a base, whatever that remains in the base is known as the CONJUGATE acid of that base*

Please read this πŸ‘†πŸ½again so you can memorize it.

In definition, we say that…πŸ‘‡πŸΌ

A *CONJUGATE BASE* is the substance gotten when a proton (or hydrogen ion) is removed from an acid.

While…πŸ‘‡πŸΌ

A *CONJUGATE ACID* is the substance gotten when a proton (or hydrogen ion) is added to a base.

In summary,πŸ‘‡πŸΌ

*To find the CONJUGATE BASE* of an acid, we Β *remove a proton (hydrogen ion) for omthe acid given*

But..πŸ‘‡πŸΌ

*To find CONJUGATE ACID* of a base, we *add a proton (or one hydrogen ion* to the base given.

NOTE THIS…πŸ‘‡πŸΌ

When they want you to find conjugate acid, they will give you a base.

Also

When they want you to find conjugate base, they will give you an acid.

You need to km w thisπŸ‘‡πŸΌ

The conjugate base of a *STRONG ACID* will give you a *WEAK BASE*

Also

The Β conjugate acid of a *STRONG BASE* will give you a *WEAK ACID*

Now let us see some examples πŸ‘‡πŸΌ

*EXAMPLE ONE*

What is the conjugate base of the acid HCl ?

*SOLUTION*…πŸ‘‡πŸΌ

In order to find conjugate base of an acid given to us, all we need to do is to remove one hydrogen ion from the acid given.

πŸ‘‰πŸΌ *Answer = Cl–*

NOTE…πŸ‘‡πŸΌ

Whenever you remove one hydrogen from a substance, you add one negative charge to the remaining substance.

But

When you add one hydrogen to a substance, you add one positive charge to the remaining substance.

*EXAMPLE Β TWO*

Find the conjugate acid of CN–.

πŸ‘‡πŸΌπŸ‘‡πŸΌπŸ‘‡πŸΌπŸ‘‡πŸΌπŸ‘‡πŸΌ

*SOLUTION*

In order to find the conjugate acid, we add one hydrogen to the remaining substance.

πŸ‘‰πŸΌ *Answer = HCN*

NOTE..πŸ‘‡πŸΌ

After adding the hydrogen and one positive charge to CN–, the positive charge added will neutralize or cancel the negative charge present in the CN– and the substance will become neutral.

*PLEASE NOTE THIS…*πŸ‘‡πŸΌ

*The difference between an acid and it’s conjugate base that*πŸ‘‡πŸΌ

The acid will have one hydrogen Β higher than it’s conjugate base.

For instanceπŸ‘‡πŸΌ

The conjugate base of *HBr* acid is *Br–*

πŸ‘‡πŸΌπŸ‘‡πŸΌπŸ‘‡πŸΌπŸ‘‡πŸΌπŸ‘‡πŸΌ

Do not forget to add a negative charge after removing one hydrogen.

πŸ‘‡πŸΌ

As you can see, the difference the acid *HBr* has one hydrogen higher than it’s conjugate base *Br–*

*Who can tell us the answer to this one*? ……πŸ‘‡πŸΌ

QUESTION.

*What is the conjugate base of tetraoxosulphate(vi) acid (H2SO4) acid* ?

*SOLUTION*πŸ‘‡πŸΌπŸ‘‡πŸΌπŸ‘‡πŸΌ

To find the conjugate base of an acid, we remove one hydrogen from the acid and then add one negative charge on the remainder.

*ANSWER πŸ‘‰πŸΌ HSO4–*

*TRY THIS ONE…*πŸ‘‡πŸΌ

QUESTION…πŸ‘‡πŸΌ

*what is the conjugate base of this acid πŸ‘‰πŸΌ H2CO3* ?

*SOLUTION*πŸ‘‡πŸΌπŸ‘‡πŸΌπŸ‘‡πŸΌ

To find the conjugate base of an acid, we remove one hydrogen from the acid and then add one negative charge on the remainder.

*ANSWER πŸ‘‰πŸΌ HCO3–*

Okay, let’s try some in conjugate acid.

*QUESTION ONE*..πŸ‘‡πŸΌ

*What is the conjugate acid of this πŸ‘‰πŸΌ NH2–* ?

*SOLUTION*πŸ‘‡πŸΌπŸ‘‡πŸΌπŸ‘‡πŸΌ

To find conjugate acid, we add one hydrogen to the base given to us and then we add one positive charge on the remainder.

*ANSWER πŸ‘‰πŸΌ NH3*

Note that when we add one positive charge to *NH2–* , the one positive charge we added will cancel that one negative charge there making the compound to become neutral(no charge).

Assuming there are two negative charges there, if we add one positive charge to it, the one positive charge we added will cancel only one of those two negative charges present thereby leaving the compound with only one negative charge.

In that case, the answer will carry one negative charge after adding the one hydrogen to it.

*Let me see who can tell us the answer to this…*πŸ‘‡πŸΌ

I AM THE CATALYST…08068113736

*SOLUTION*…πŸ‘‡πŸΌ

The chemical formula for water is πŸ‘‰πŸΌ *H2O*

πŸ‘‡πŸΌπŸ‘‡πŸΌπŸ‘‡πŸΌ

*SOLUTION*πŸ‘‡πŸΌπŸ‘‡πŸΌπŸ‘‡πŸΌ

To find conjugate acid, we add one hydrogen to the base given to us and then we add one positive charge on the remainder.

*ANSWER πŸ‘‰πŸΌ H3O^+*

NOTE that there was no charge present in the compound given (H2O).

Therefore, the positive charge we added will appear because there is no negative charge there to us and cancel it.

*LET US NOW TAKE A LOOK AT*…πŸ‘‡πŸΌ

BASICITY Β OF Β ACIDS.

*BASICITY* of an acid is defined as the total number of the ionizable hydrogens present in an acI’d.

When we say the total number of ionizable hydrogens in the acid, we meanπŸ‘‡πŸΌ

*the total number of free hydrogen ions that would be produced when the acid breaks up or dissociates in an aqueous solution*

Assuming the total number of hydrogen atoms present in an acid is four, but Β only one out of the four hydrogens in the acid can be set free from the acid when the acid undergoes ionization or break-upπŸ‘‡πŸΌ

*then the BASICITY of that acid is said to be 1.

NOTE thatπŸ‘‡πŸΌ

*In order to determine the BASICITY of a given acid, you need to know how the acid dissociates*

When strong acids dissociate (break up), they produce all the hydrogens present in them. Therefore, we say that *strong acids undergo COMPLETE IONIZATION*

Also

When weak acids dissociate, they produce some (not all) of their hydrogens present in them. Therefore we say that *weak acids undergo PARTIAL IONIZATION*

*Examples…*πŸ‘‡πŸΌπŸ‘‡πŸΌπŸ‘‡πŸΌ

H2SO4 and H3PO4 are strong acids. Therefore, when they dissociate, πŸ‘‡πŸΌ

H2SO4 –> *2H^+* + Β *SO4^²–*

and

H3PO4 —> *3H^+* Β + Β *PO4^³–*

They produce all the hydrogens in them without leaving any hydrogen behind (complete ionization)

*Since H2SO4 produces two hydrogens when it ionizes, we say that the BASICITY of H2SO4 is πŸ‘‰πŸΌ 2*

Also

*Since H3PO4 produces three hydrogens when it ionizes, we say that the BASICITY of H3PO4 is πŸ‘‰πŸΌ 3*

NOTE that πŸ‘‡πŸΌ

*organic acids are weak acids*. They undergo partial ionization.

Example..πŸ‘‡πŸΌ

*Ethanoic acid* πŸ‘‰πŸΌ CH3COOH.

on ionizationπŸ‘‡πŸΌ

*CH3COOH* –> *CH3COO^–* + *H^+*

As you can seeπŸ‘†πŸ½, out of the total of four hydrogens present in ethanoic acid, only one of the hydrogens is produced on ionization (partial ionization). This is because they have only one hydrogen at their functional groups (COOH).

πŸ‘‡πŸΌπŸ‘‡πŸΌπŸ‘‡πŸΌπŸ‘‡πŸΌπŸ‘‡πŸΌ

*Propanoic acid* πŸ‘‡πŸΌ

*CH3CH2COOH* –> *CH3CH2COO^–* + *H^+*

Out of the total of six πŸ‘†πŸ½hydrogens, only one hydrogen is produced (partial ionization)

I AM THE CATALYST…08068113736

*NOTE*…πŸ‘‡πŸΌ

Organic acids that have two COOH groups in them will produce two hydrogens when they ionize….πŸ‘‡πŸΌ

For instance..πŸ‘‡πŸΌ

*Ethanedioic acid*

*HOOCCOOH* –> *(COO^–)2* + *2H^+*

NB:- πŸ‘‰πŸΌ *dioic* means two COOH groups present.

Acids that produce only one hydrogen ion when they ionize are said to be *monobasic*

Acids that produce two hydrogen ions on dissociation are said to be *dibasic*.

Acids that produce three hydrogen ions on dissociation are said to be *tribasic*.

*Generally,*…πŸ‘‡πŸΌ

Organidioic organic acids* which are *dibasic*

I AM THE CATALYST…08068113736.

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