Did someone call a chemist?

The Germans filled there airships with hydrogen (they very limited amounts of helium) by reacting iron with HCl (hydrochloric acid) and/or sulfuric acid. To calculate the amount of hydrogen you'll produce you need to know the concentration of the acid in "moles". For every one mole of HCl you'll get 1/2 mole of hydrogen gas. For each mole of sulfuric acid you'll get one mole of hydrogen gas.

The next step is calculating the number of moles of hydrogen gas needed to fill a volume. The equation there is V=nRT / P where
V = volume in liters
T = temperature in Kelvin (75 F = 297 K)
P = pressure in atmospheres (atm)
n = moles of hydrogen gas (mole)
R = Universal gas constant = 0.08206 L*atm/mole*K)

So, on a nice day let's say you want to fill a 55-gal drum with hydrogen. 55 gallons is equal to 208 liters, the temperature outside is a pleasent 75 F and there are no hurricanes in the forcast so the barometric pressure equals 1 atmosphere. This makes your equation:
n = PV / RT

n = [1 atm*208 L] / [(0.08206 L*atm/mole*K)* 297K]

n = 8.5 moles hydrogen gas

Calculating the amount of acid required to produce this many moles of hydrogen gas is being left to the reader, however you can PM me if you want detailed calculations.

Um, it goes without saying that you shouldn't be smoking while attempting this.

-Mark, who still claims the ten years of college wasn't a waste. <img src="/images/graemlins/crazy.gif" alt="" />