If we have H2O, D2O (D stands for deuterium), and Na, how would we react these to form HD pure gas?
The answer was:
Na + H2O --> NaOH + (1/2) H2
Na + (1/2)H2 --> NaH
NaH + D2O --> HD + NaOD
How is this the answer? How would we know which compounds to react and such?