Answer to Question #90116 in Chemistry for Vaibhavi Desai

Question

(a) What is the oxidation number of the named element in the following compounds?

(i) manganese in Mn2O7

(ii) Iron in Fe(CN)6^3

Answer 1

Task:

(a) What is the oxidation number of the named element in the following compounds?

(1) manganese in Mn₂O₇;

(2) Iron in [Fe(CN)₆]^3-.

Solution (1):

(1) Mn₂O₇

The oxidation state of the oxygen is -2, and the sum of the oxidation states is equal to zero.

2*n + 7*(-2) = 0;

2*n = 14;

n = +7.

The oxidation number of the Mn in Mn₂O₇ is +7.

Answer (1): Mn(+7).

Solution (2):

The oxidation state of the cyanide group (CN^-) is -1, and the sum of the oxidation states is equal to the charge on the ion.

n + 6*(-1) = -3;

n = 6-3 = 3;

n = +3.

The oxidation number of the Fe(iron) in [Fe(CN)₆]^3- is +3.

Answer (2): Fe(+3).