NaF + Br2 à NaBr + F2 A. ---, 2, 2, ---

B. 2, ---, ---, 2

C. 2, ---, 2, ---

2 NaF + Br2 --> 2NaBr + F2

Explanation:

Well first I notice that there are two flourines on the products side so we need to put a 2 of NaF. Now there are 2 sodiums on the products side so we have to put another two in front of NaBr.

2 NaF + Br2 --> 2NaBr + F2

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