Answer:
C
H²O is dissociated in water into H³O+ (hydronium ions) and OH- (hydroxide) given by;
2H²O <-----> H³O+ + OH-
If you notice initially we have 4 hydrogen atoms and 2 oxygen atoms. And similarly after the reaction we have 4 hydrogen atoms and 2 oxygen atoms.
Ratio of H to O is 4:2
or 2:1
This is very intuitive as we have 2 hydrogen atoms and 1 oxygen atom in a water molecule.
