Justify that the following reactions are redox reactions:
2K(s) + F2 (g) → 2K + F–(s)
Let us write the oxidation number of each element involved in the given reaction as:
K = 0 & + 1
F = 0 &-1
Oxidation number of K increases from 0 in K to + 1 in KF i.e. K is oxidised to KF. on the other hand, the O.N. of F decreases from 0 in F2 to -1 in KF i.e. F2 is being reduced to KF.
Hence, the given reaction is a redox reaction.