Naming and Writing acids

What are Binary Acids?

Binary means two elements

Acid means it contains hydrogen

The second element is a nonmetal

hydrogen – nonmetal

Naming

All binary acids follow the pattern as shown below:

Prefix

Hydro-

Stem or root of nonmetal

< NM >

Suffix

-ic Acid

HCl Hydro

HI Hydro

HCl is a binary acid – hydrogen - nonmetal

chlor ic Acid

iodic Acid

H2S Hydro sulfur ic Acid

Given the name, how do you write formulas for binary acids?

The obvious pattern of the name tells you that it is a binary acid. Hydro<NM>ic Acid.

Therefore, you know that the acids begins with hydrogen and contains a nonmetal which you can identify between the “Hydro” and the “ic”

To arrive at the formula, you “pretend” that hydrogen is +1 and using the normal charge of the nonmetal, balance the formula by supplying subscripts.

Hydrofluoric Acid The name tells you that this is a binary acid.

H+1 F-1

HF

Hydrophosphoric acid The name tells you that it is definitely a binary acid.

H+1 P-3

Remember that the P has a -3 charge because it is in group 15

H3P

Let’s Practice

Ca(OH)2

Calcium hydroxide

SO2

Sulfur dioxide

(NH4)3PO4

Ammonium phosphate

Co2(CO3)3

Cobalt (III) carbonate

HBr

Hydrobromic acid

Ternary Ionic

Binary molecular

Ternary Ionic

Ternary Ionic

Binary acid

Potassium acetate

KC2H3O2

Cadmium nitrate

Cd(NO3)2

Aluminum oxide

Al2O3

Hydrosulfuric acid

H2S

Difluorine trioxide

F2O3

Ternary Ionic

Ternary Ionic

Binary Ionic

Binary acid

Binary molecular

The fifth category of compounds is Ternary Acids. These compounds begin with hydrogen since they are “acids”.Attached to the hydrogen is a polyatomic ionHydrogen – polyatomic ion

<Root of polyatomic ion>

suffix

-ic acid

HClO3 Chlor

HNO3Nitr

H2SO4 Sulfur

HCN Cyan

How are Ternary Acids named?There are two categories of naming depending on the suffix of the polyatomic ion.First Category: If the polyatomic ion has a suffix of –ate or –ide, use the following pattern:

Ternary Acid – contains the polyatomic ion chlorate (suffix –ate)

Ternary Acid – contains the polyatomic ion nitrate (suffix –ate).

Ternary Acid – contains the polyatomic ion sulfate (suffix –ate).

Ternary Acid – contains the polyatomic ion cyanide (suffix –ide).

ic Acidic Acid

ic Acid

ic Acid

Second Category: If the polyatomic ion has a suffix of –ite, use the following pattern:

<Root of polyatomic ion>

suffix

-ous acidHNO2

Ternary acid contains polyatomic ion, nitrite (-ite suffix).

Nitr ous acid

HClO2 Ternary acid contains polyatomic ion, chlorite (-ite suffix).

Chlor ous acid

H2SO3Ternary acid contains polyatomic ion, sulfite (-ite suffix).

Sulfur ous acid

How are Ternary Acids named?

First, a ternary acid is easy to distinguish from a binary acid.

ALL binary acids have the prefix “hydro-”.

NO Ternary acids have the prefix “hydro-”.

Acetic acid This is an acid, but NOT a binary acid.

This is a ternary acid.

The “-ic” suffix in the acid name tells you that the polyatomic ion must have a “-ate” suffix – acetate.

To write the formula, pretend that hydrogen is +1 and balance the charges.

H+1 C2H3O2-1

HC2H3O2

Hypochlorous acid This is a Ternary acid (does not begin with “hydro-”.

The “-ous” suffix indicates that the polyatomic ion in this acid has a suffix of “-ite” - hypochlorite

Pretend that hydrogen is +1 and balance the charges.

H+1 ClO-1

HClO

Phosphoric acid This is a Ternary acid (does not begin with “hydro-”.

The “-ic” suffix indicates that the polyatomic ion in this acid has a suffix of “-ate” - phosphateH3PO4

Pretend that hydrogen is +1 and balance the charges.

This concludes Module 13!