Alkali metal roulette

Students generally make three requests after seeing the reaction of alkali metals with water: ‘Put in a bigger piece!’, ‘Can we see what happens with caesium?’ and ‘What happens if you do it in acid?’.

Safety prohibits the use of bigger pieces, while cost and practical considerations prohibit the use of caesium. But, perhaps surprisingly, the reaction with concentrated hydrochloric acid can be safely performed.

With an accompanying video, Declan Fleming shows how to perform this experiment safely with hydrochloric acid, going from set up to demonstration and class discussion.