I believe the correct answer from the choices listed above is the first option. When Br2 and NaF are mixed, no reaction would occur since Br cannot replace F in NaF. By looking at the positions of the halogens in the periodic table, bromine is located way below fluorine. Reactivity of bromine would be low as compared to fluorine so it will not have enough energy to replace fluorine in the compound as it will not have sufficient energy to bind. The position of the halogens are F, Cl, Br, I and At where fluorine is the most reactive element.
