Question

Assertion: \[{I_2}{O_5}\] is used to detect \[CO\]
Reason: In \[{I_2}{O_5}\] the oxidation number of \[I\] is \[5\]
a.Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
b.Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
c.Assertion is correct but Reason is incorrect.
d.Both Assertion and Reason are incorrect.

Answer 1

Hint: Iodine pentoxide is an important gas and a chemical compound made up of two iodine atoms and five oxygen atoms. It can also be defined as the anhydrate of iodic acid and tends to show reaction with carbon monoxide gas.

Complete answer:
Iodine pentoxide can be used in the quantitative as well as qualitative determination of carbon monoxide gas. The reaction between Iodine pentoxide and carbon monoxide is a redox reaction in which carbon monoxide gets oxidized to carbon dioxide and iodine pentoxide gets reduced to iodine present in its diatomic atom. The reaction between iodine pentoxide and carbon monoxide can be written as follows:
\[{I_2}{O_5} + 5CO \to {I_2} + C{O_2}\]
The formation of solid iodine which is violet-purple in colour indicates the presence of carbon monoxide gas in any gaseous sample when it reacts with iodine pentoxide.
The oxidation state of iodine in iodine pentoxide can be determined by assuming that the oxidation number of iodine in the given compound is \[x\] and we know that the oxidation number shown by each oxygen atom is always equal to \[ - 2\] . The overall compound is neutral and therefore the total oxidation number should become equal.
By multiplying the oxidation number of each element by the stoichiometric number in which its atoms are present in the molecule and solving the equation in one variable we get,
\[2x + 5 \times ( - 2) = 0\]
\[x = 5\]
Thus, the oxidation number of iodine in the compound iodine pentoxide is five.
Hence, both the assertion and reason are correct individually but there is no relation between the oxidation state of iodine and the detection of carbon monoxide gas.

Therefore, the correct option is (b) both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.

Note:
Carbon monoxide is a toxic gas and can be lethal even when inhaled in small amounts due to its ability to replace oxygen as a ligand. Therefore it is important to detect the presence of carbon dioxide in gaseous samples and also determine its concentration.