Which gas did Jacques Charles discover could be used as the source of hot air for a hot air balloon's envelope?

1 Answer
Dec 15, 2016

Old Jacques Charles pioneered the use of hydrogen balloons..........


According to this site M. Charles used the action of sulfuric acid on iron filings to fill his bladders:

#Fe(s) + H_2SO_4(aq) rarr H_2(g) + FeSO_4(aq)#.

Charles was a contemporary of the Montgolfier brothers, who used the considerably safer hot air balloons. Why would hydrogen ballooning be inherently unsafe?