Question

Determine the oxidation state for each of the elements below.

The oxidation state of	...	phosphorus	...	in	...	phosphorous tribromide PBr3	...	is	...
The oxidation state of		carbon		in		carbon monoxide CO		is
The oxidation state of		oxygen		in		potassium peroxide K2O2		is

Answer 1

1)

Oxidation number of Br = -1

lets the oxidation number of P be x

use:

3* oxidation number (Br) + 1* oxidation number (P) = net charge

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

-3 + 1 * x = 0

x = 3

So oxidation number of P = +3

Answer: +3

2)

Oxidation number of O = -2

lets the oxidation number of C be x

use:

1* oxidation number (O) + 1* oxidation number (C) = net charge

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

-2 + 1 * x = 0

x = 2

So oxidation number of C = +2

Answer: +2

3)

This is ionic compound of K+ and O2-2

lets the oxidation number of O be x

use:

1* oxidation number (O) = net charge

2* x = -2

2 * x = -2

x = -1

So oxidation number of O = -1

Answer: -1