`Br_2` undergoes disproportionation reaction in basic medium to give `Br^(ɵ)` ion and `BrO_3^(ɵ)` (bromate) ion in reduction and oxidation reaction.

Explanation

`Br_2+2e^(-)to2Br^(ɵ)(n=2)` (reduction)
`Br_2+12overset(ɵ)(O)Hto2BrO_3^(ɵ)+6H_2O+10^(e-)(n=10)` (oxidation)
`Ew(Br_2)=(Mw(Br_2))/(2)+(Mw(Br_2))/(10)`
Alternatively, `Ew(Br_2)`
`Mw(Br_2)((1)/(2)+(1)/(10))`
`=Mw(Br_2)xx(6)/(10)`
`=(80xx2xx6)/(10)=96g`
`:.` n-factor of `Br_2=(10)/(6)`
`:. Ew(Br_2)=(Mw(Br_2))/("mean n-factor")=(Mw(Br_2))/((10)/(6))`
`=(6xxMw(Br_2))/(10)`