The percentage of oxygen in NaOH is

The percentage of oxygen in air is-

Give reasons for the following: The percentage of oxygen, in air dissolved in water, is higher than the percentage of oxygen in ordinary air.

The percentage of oxygen in heavy water is

The percentage of oxygen in a compound is determined by

The percentage of oxygen in CH_(2) O is

The percentage of oxygen in CH_(2) O is

The percentage of oxygen in the protoplasm of cell.