Q.

Consider the following compounds:
K-O2,H2O2- and H2S-O4
The oxidation states of the underlined elements in them are, respectively,             [2025]

1 +1, −2 and +4  
2 +4, −4 and +6  
3 +1, −1 and +6  
4 +2, −2 and +6  

Ans.

(3)

KO2 ionises as K+ and O2- ions as it is a superoxide.

Thus, oxidation state of K is +1.

H2O2 ionises as H+ and O22- as it is a peroxide.

Oxidation state of each O in O22- is -1.

In H2SO4, let the oxidation state of S be x; hence

2(+1)+x+4(-2)=0

2+x-8=0

x=+6