Question

An oxide of iodine contains 25.4 g of iodine for 8 g of oxygen. Its molecular formula will be-
A.${I_2}{O_3}$
B.${I_2}O$
C.${I_2}{O_5}$
D.${I_2}{O_7}$

Answer 1

Iodine oxides are oxygen-iodine chemical compounds. Only two stable oxides of iodine, iodine trioxide and iodine pentoxide, are isolatable in bulk, although a variety of additional oxides are produced in small amounts or have been theorised to exist. The chemistry of these substances is complex, and only a handful have been thoroughly investigated. Many have been discovered in the atmosphere, and they are thought to play a key role in the marine boundary layer.

Complete answer:
The empirical formula of a chemical compound is the simplest positive integer ratio of atoms present in the molecule, as defined in chemistry. Their molecular formulae, on the other hand, which represent the number of atoms in each molecule of a chemical compound, are not identical. In contrast, the molecular formula indicates the number of each sort of atom in a molecule. The structural formula depicts the molecule's configuration. Different types of compounds can also have empirical formulae that are equivalent. Specific elemental analysis tests are used to identify what percentage of a particular element is present in a sample.

Element	Mass	Atomic mass	Number of moles	Simplest Ratio	Whole number
I	25.4	127	$\dfrac{{25.4}}{{127}} = 0.2$	$\dfrac{{0.2}}{{0.2}} = 1$	2
O	8	16	$\dfrac{8}{{16}} = 0.5$	$\dfrac{{0.5}}{{0.2}} = 2.5$	5

Hence it can be expressed as ${I_2}{O_5}$

Note:
The chemical compound ${I_2}{O_5}$ stands for iodine pentoxide. This is the only stable iodine oxide, as it is the anhydride of iodic acid. It's made by dehydrating iodic acid in a stream of dry air at $200^\circ C$:
$2HI{O_3}\; \to {\text{ }}{I_2}{O_5}\; + {\text{ }}{H_2}O$