Question

What is wrong with each of the following ionic compounds? There may be more than one error in each. Please state what the specific error is clearly and concisely and then "fix" it.

a) (NO₃)₂SO₄

b) FeF

c) Ca(OH₂)

d) Ir(II)I₂

Answer 1

a) (NO₃)₂SO₄

There is no error in (NO₃)₂SO₄. Charge of NO₃ is +1 & charge of SO₄ is -2. Common charge is 2.

NO₃ = Charge of NO₃ X Charge of ion in compound = common charge

NO₃ = 1 X 2 = 2

SO₄ = Charge of SO₄ X Charge of ion in compound = common charge

SO₄ = 2 X 1 = 2

So, (NO₃)₂SO₄ is correct.

b) FeF

Charge of Feis +2 or +3 & charge of Fis -1. Common charge is 2 or 3.

Fe = 2 X 1 =2 or 3 X 1 =3

F = 1 X 2 =2 or 1 X 3 =3

The formula of ionic compound is Fe(II)F₂ or Fe(II)F₃

c) Ca(OH₂)

Charge of Cais +2 & charge of OHis -1. Common charge is 2.

Ca = 2 X 1 =2

OH = 1 X 2 =2

The formula of ionic compound is Ca(OH)₂

d) Ir(II)I₂

Charge of Iris +3 or +4 & charge of Iis -1. Common charge is 3 or 4.

Ir = 3 X 1 =3 or 4 X 1 = 4

I = 1 X 3 =3 or 1 X 4 =4

The formula of ionic compound is Ir(III)I₃ or Ir(IV)I₄