What is the oxidation number of chlorine in potassium trioxochlorate(V), \text{KClO}_3? — JAMB UTME

What is the oxidation number of chlorine in potassium trioxochlorate(V), $\text{KClO}_3$ ?

The oxidation number of chlorine in

\text{KClO}_3

+5

In potassium trioxochlorate(V),

\text{KClO}_3

, potassium contributes

+1

and three oxygen atoms contribute a total of

-6

. For the compound to be electrically neutral, chlorine must have an oxidation state of

+5

Assign known oxidation numbers to potassium and oxygen

Potassium (Group 1 metal) has an oxidation state of

+1

. Oxygen has an oxidation state of

-2

Standard rules assign

+1

to alkali metals and

-2

to oxygen in oxoacids/oxoanions.

Formulate an equation for the neutral molecule

\text{KClO}_3

(+1) + x + 3(-2) = 0

The sum of all oxidation numbers in a neutral chemical compound must equal zero.

Solve for the unknown oxidation state

x

of chlorine

+1 + x - 6 = 0 \implies x - 5 = 0 \implies x = +5

Solving the linear algebraic equation yields

+5

Oxidation state calculation of halogens in oxoacids and oxoacid salts

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