What should you have on hand to stop the action of bromine?

What should you have on hand to stop the action of bromine?

• A. Ammonia water
• B. Magnesium hydroxide
• C. Water
• D. Spirit of ammonia

Answer: (A)

The key idea here is having a substance that rapidly neutralizes or scavenges bromine so the reaction cannot continue. Bromine is very reactive, and in a monitoring or lab setting you want something that quickly removes Br2 from the mixture. Ammonia in water provides a ready source of NH3 in solution that reacts with bromine to form ammonium bromide and related nitrogen–bromine species, effectively quenching the bromine’s activity and stopping further bromination. Water alone would only dilute and slowly hydrolyze Br2, not stop its action promptly. Spirit of ammonia (ammonia in alcohol) can still work but is not as reliable or efficient in quenching bromine quickly in many practical setups. Magnesium hydroxide isn’t a fast bromine scavenger, so it wouldn’t stop the action effectively. So, having ammonia water on hand is the best choice to stop the action of bromine.

The key idea here is having a substance that rapidly neutralizes or scavenges bromine so the reaction cannot continue. Bromine is very reactive, and in a monitoring or lab setting you want something that quickly removes Br2 from the mixture. Ammonia in water provides a ready source of NH3 in solution that reacts with bromine to form ammonium bromide and related nitrogen–bromine species, effectively quenching the bromine’s activity and stopping further bromination. Water alone would only dilute and slowly hydrolyze Br2, not stop its action promptly. Spirit of ammonia (ammonia in alcohol) can still work but is not as reliable or efficient in quenching bromine quickly in many practical setups. Magnesium hydroxide isn’t a fast bromine scavenger, so it wouldn’t stop the action effectively. So, having ammonia water on hand is the best choice to stop the action of bromine.