JEE MainChemistryp Block Elements (Group 15, 16, 17 & 18)
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The reaction of I₂ with water is non-spontaneous, whereas I^- can be oxidised by O₂ in acidic medium. Reason (R): The standard reduction potential E^ _ I₂/I^- is lower than E^ _ O₂/H₂O . In the light of the above statements, choose the most appropriate answer from the options given below.
Options
- ABoth (A) and (R) are correct but (R) is not the correct explanation of (A).
- B(A) is correct but (R) is not correct.
- C(A) is not correct but (R) is correct.
- DBoth (A) and (R) are correct and (R) is the correct explanation of (A).
Correct answer
D. Both (A) and (R) are correct and (R) is the correct explanation of (A).
Step-by-step solution
Assertion (A) is correct. Unlike fluorine, chlorine, and bromine, iodine does not react with water spontaneously. Instead, the reverse reaction takes place, where iodide ions ( I^- ) are oxidised by oxygen in an acidic medium to form I₂ . Reason (R) is correct and provides the correct explanation for (A). A redox reaction is spontaneous if the oxidising agent has a higher standard reduction potential than the species being oxidised. Since E^ _ O₂/H₂O > E^ _ I₂/I^- , oxygen acts as a stronger oxidising agent than io