n L出氢气为n/22.4mol,须有2n/22.4mol的HCl才能提供,故就是2n/22.4mol
n L产生n/22.4mol氢气,要和2n/22.4mol的HCl反映所以是2n/22.4mol
(n/22.4)*2
(n\22.4)*2