Fluorine reacts with ice and results in the change:
`H_(2)O(s) + F_(2)(g) to HF(g) + HOF(g)`
Justify that this reaction is a redox reaction .

Explanation

Here, `F_(2)` is reduced to `HF` and oxidised to `HOF`, therefore, it is redox reaction. `HOF` is an highly unstable molecule and hence decomposes to form `O_(2)` and `HF`.
`overset(+1)(2H)overset(-2)(O)overset(+1)(F)rarr 2overset(+1)(H)overset(-1)(F)+overset(0)(O_(2))`
In this reaction, `F` of `HOF` is reduced while `O` of `HOF` is oxidised. Therefore, it is a redox reaction but not a disproportionation reaction. If oxygen of `HOF` disproportionates, then oxygen must have three oxidation states. If we assume that the oxidation state of oxygen is zero in `HOF`, then it can decrease its oxidation state to `-2` if `HOF` gets reduced to `H_(2)O` and to `+2` if `HOF` gets oxidised to `OF_(2)`. Therefore,
`overset(+1)(2H)-overset(0)(O)-overset(-1)(F)rarr overset(+1)(H_(2))overset(-2)(O)+overset(+2)(O)overset(-1)(F_(2))`