5
3
2
4
Reaction of Br2 with Na2CO3 in aqueous solution gives sodium bromide and sodium bromate with evolution of CO2 gas. The number of sodium bromide molecules involved in the balanced chemical equation is 5. 3Na2CO3 + 3Br2 → 5NaBr + NaBrO3 + 3CO2 Hence, the correct option is A.