In which of the following compounds is the oxidation number of iodine fractional?

Oxidation number of $Cl$ in $CaOCl_2$ (bleaching powder) is

In chromite ore,the oxidation number of iron and chromium are respectively

What are the oxidation numbers of the underlined elements in each of the following and how do you rationalise your results?
$(a)$ $K\underline {I_3}$
$(b)$ $H_2\underline {S_4}O_6$
$(c)$ $\underline {Fe_3}O_4$
$(d)$ $\underline {C}H_3\underline {C}H_2OH$
$(e)$ $\underline {C}H_3\underline {C}OOH$

Calculate the oxidation number of each sulfur atom in the following compounds:
$Na_2S_2O_3$
$Na_2S_4O_6$
$Na_2SO_3$
$Na_2SO_4$

The oxidation states of sulfur atoms and the number of $S-OH$ bonds in Peroxydisulfuric acid are respectively: