Question

The permanganate anion has the formula MnO₄-. Propose formulas and names for the ionic compounds between the permanganate ion and K⁺, Ca²⁺, and Fe³⁺ .

Answer 1

Sol . As

Permanganate anion - MnO₄^- , Potassium cation - K⁺ , Calcium cation - Ca²⁺ , Iron cation - Fe³⁺

Now , In writing the name of compound , firstly name of cation is wrtiiten with its charge in brackets() and then name of anion is written .

Also , In writing the formulae of compound , firstly formulae of cation written and then formulae of anion written and charge present on cation is written at the subscript of anion and charge present on anion is written at the subscript of cation . And charge of +1 or -1 need not to be wriiten at subscript of cation and anion .

1.

Ionic compound between K⁺ and MnO₄^-  

Name of compound --> Potassium (I) Permanganate

Formulae of compound --> KMnO₄

As K⁺ has +1 charge and MnO₄^- has -1 charge , so, firstly K is written with subscript of 1 and then MnO₄ is wriiten with subscript of 1 , that is , K₁(MnO₄)₁ , or , KMnO₄  

2.

Ionic compound between Ca²⁺ and MnO₄^-  

Name of compound --> Calcium (II) Permanganate

Formulae of compound --> Ca(MnO₄)₂

As Ca²⁺ has +2 charge and MnO₄^- has -1 charge , so, firstly Ca is written with subscript of 1 and then MnO₄ is wriiten with subscript of 2 , that is , Ca₁(MnO₄)₂ , or , Ca(MnO₄)₂

3.

Ionic compound between Fe³⁺ and MnO₄^-  

Name of compound --> Iron (III) Permanganate

Formulae of compound --> Fe(MnO₄)₃

As Fe³⁺ has +3 charge and MnO₄^- has -1 charge , so, firstly Fe is written with subscript of 1 and then MnO₄ is wriiten with subscript of 3 , that is , Fe₁(MnO₄)₃ , or , Fe(MnO₄)₃