Question

Which of the following sequences is correct with reference to the oxidation number of iodine?
A. \[{{I}_{2}} \ \ < \ \ ICl \ \ < \ \ HI \ \ < \ \ HI{{O}_{4}}\]
B. \[HI{{O}_{4}} \ < \ ICl \ < \ {{I}_{2}} \ < \ HI\]
C. \[{{I}_{2}} \ < \ HI \ < \ ICl \ < \ HI{{O}_{4}}\]
D. \[HI \ < \ {{I}_{2}} \ < \ ICl \ < \ HI{{O}_{4}}\]

Answer 1

\ < \ b>Hint: \ < \ /b> Oxidation state of a species is defined as the charge on the species. Due to its large size, iodine can show multiple oxidation states.

 Complete Step by Step Answer:
The given compound is $HI{{O}_{4}}$ .
Let the oxidation state of iodine is $x$ . The charge of the hydrogen atom is $+1$ and the charge on the oxygen atom is $-2$ .
Thus we can write,
$x+1+4\times (-2)=0$
$x=+7$
The given compound is $HI$ .

Let the oxidation state of iodine is $x$ . The charge of a hydrogen atom is $+1$.
Thus we can write,
$x+1=0$
$x=-1$
The given compound is $ICl$ .

Let the oxidation state of iodine is $x$ . The charge of chlorine atoms is $-1$ .
Thus we can write,
$x-1=0$
$x=+1$
The oxidation state of iodine in iodine gas is zero.
 Thus the correct option is D.

 Additional Information: Iodine is a halogen element. It has the symbol of $I$. It generally exists as a gas. It has the colour of violet blue. Iodine is generally obtained from seaweed.
Starch generally acts as an indicator in titration reactions to determine the end point of a titration. Iodine gas reacts with starch, an indicator gives blue colour.

 Note: High oxidation state or positive oxidation state indicates the oxidising power of a species and low oxidation state or negative oxidation state indicates reducing power of a species.