Question

Amongst the following, identify the species with an atom in +6 oxidation state.
A. \[\text{(Mn}{{\text{O}}_{4}}\text{)}\]
B. \[{{\text{(Cr(CN}{{\text{)}}_{6}}\text{)}}^{-3}}\]
C. \[\text{(C}{{\text{r}}_{2}}{{\text{O}}_{3}}\text{)}\]
D. \[\text{(Cr}{{\text{O}}_{2}}\text{C}{{\text{l}}_{2}}\text{)}\]

Answer 1

Hint: For this problem, we have to calculate the oxidation state of the central atom present in the given molecules. For calculating the oxidation state of the element, we have to consider it as 'x' and then by putting the oxidation state of other elements we can calculate the value of x.

Complete step by step answer:
- In the given question, we have to calculate the oxidation state of the given molecules and explain which element will have the oxidation state of +6.
- As we know that the oxidation state is the number of electrons that an element will lose and gain while forming the bond.
- So, firstly we will calculate the oxidation state of the \[\text{(Mn}{{\text{O}}_{4}}\text{)}\], in which we will let the oxidation state of manganese as 'x' and we will get:
$\text{x + (4 }\times \text{ -2) = 0}$; $\text{x = +8}$
- Now, the oxidation state of chromium in \[{{\text{(Cr(CN}{{\text{)}}_{6}}\text{)}}^{-3}}\] will be:
$\text{x + (1 }\times \text{ -6) = -6}$; $\text{x = 0}$
- So, both A and B will not be the correct answer.

- Now, we will calculate the oxidation state of chromium in the third given compound that is \[\text{(C}{{\text{r}}_{2}}{{\text{O}}_{3}}\text{)}\].
- Similarly, let the oxidation state of chromium as x then we will get:
$\text{2x + (6 }\times \text{ -2) = 0}$; $\text{x = +6}$
- As the oxidation state of chromium is +6. So, we can say that it is the correct option.
- Now, in the last option \[\text{(Cr}{{\text{O}}_{2}}\text{C}{{\text{l}}_{2}}\text{)}\], let the oxidation state of chromium as x and by adding the oxidation state of oxygen and chlorine we will get:
$\text{x + (2 }\times \text{ -2) + (-2) = 0}$; $\text{x = +6}$
- So, option D is also correct as the oxidation state of chromium is +6.
So, the correct answer is “Option C and D”.

Note: The oxidation state of the element tells us the number of bonds that will be formed by it with the adjacent atoms. The oxidation state of the element may vary according to the atom with which it makes bond.