How many hydrogen ions must be added to the half-reaction to balance the mass of hydrogen atoms?

Question

CN ^- (aq) → CNO ^- (s)
Options:

a) 1 on the left side
b) 1 on the right side
c) 2 on the left side
d) 2 on the right side
e) no hydrogen ions are needed

Answer 1

To balance the mass of hydrogen atoms, we need to compare the number of hydrogen atoms on each side of the half-reaction.

On the left side, there is 1 hydrogen atom in CN^-.

On the right side, there is 1 hydrogen atom in CNO^-.

Since the number of hydrogen atoms is already balanced, we do not need to add any hydrogen ions.

Therefore, the correct option is e) no hydrogen ions are needed.