Question

Moist iodine reacts with ozone to form:
a.$HI$
b.$HI{O_3}$
c.${I_2}{O_3}$
d.${I_2}{O_7}$

Answer 1

Reactants: The compounds which react with each other to form a new compound, are known as reactants.
Products: The compounds which are formed when reactants react with each other, are known as products.

Complete answer:
Here we have to find the product when moist iodine reacts with ozone. The reaction is as follows:
${I_2} + 5{O_3} + {H_2}O \to 2HI{O_3} + 5{O_2}$.
Here $HI{O_3}$ is formed as a product.

So option c is correct.

Additional information:
Generally the compound whose oxidation number increases during the reaction is known as oxidised compound and the compound whose oxidation number decreases during the reaction is known as reduced compound.
Now let us first talk about the oxidations number of elements in the compounds given in the reaction.
Oxidation number of an element: It is defined as the total number of electrons that an atom accepts or loses in order to make a chemical bond which results in the formation of a chemical compound.
Oxidation: The compound which loses the electron during the reaction or the compound whose oxidation number increases during the reaction.
Reduction: The compound which gains the electron during the reaction or the compound whose oxidation number decreases during the reaction.
Here in the reaction iodine is an oxidised compound (because oxidation number increases) and ozone acts as reduced compound (because oxidation number decreases).
The compounds in options are as i) $HI$ in this compound the oxidation number of iodine is $- 1$.
ii) $HI{O_3}$ in this compound the oxidation number of iodine is $+ 5$.
iii) ${I_2}{O_3}$ in this compound the oxidation number of iodine is $+ 3$.
iv) ${I_2}{O_7}$ In this compound the oxidation number of iodine is $+ 7$.
Iodine can show more than one oxidation state because of the presence of vacant d-orbitals in its valence shell.

Note:
Generally the compound which is oxidised in the reaction will act as reducing reagent (which oxidise the other compounds) and the compound which is reduced in the reaction will act as oxidising reagent (which reduce the other compounds) for the reaction.