1.2H2O =2H2 +O2 2 1 X X/2 2D2O =2D2 + O2 2 1 Y Y/2 X+Y+X/2+Y/2=33.6L/(22.4L/mol) 2X+4Y+(X/2+Y/2)*32=18.5 解得X=0.75 Y=0.25 重氢（D）和普通氢（H）的原子个数比为:2Y/2X=0.25/0.75=1:3
