Question

In which molecule, underlined element is in +5 oxidation state ? (1) Ca, (A103)2 (3) H3PO 3 (2) K2 H2 Sb207 (4) NO2///give correct answer

Answer 1

Let x be the oxidation number of Ca in Ca(ClO2)2.

We know that the oxidation no. of oxygen = −2 but for Cl the oxidation no. is unknown. So, first, we need to find out the oxidation no. of Chlorine.

From the structure, we can see that Ca is attached with 2 ClO2− ions.

Let oxidation no. of Cl be Q,

So, Q+2×(−2)=−1

⇒Q=+3 

Since, the overall charge on the complex is 0, the sum of oxidation states of all elements in it should be equal to 0.

x+2(+3+2(−2))=0

x−2=0

x=+2

Thus, the oxidation number of Ca in Ca(ClO2)2 is +2.