What is added to balance hydrogen and oxygen atoms in an oxidation reduction reaction in acidic solution?

Water for oxygen and protons for hydrogen.

Explanation:

To balance O and H in acidic medium:-

To balance Oxygen:

Add water () where there are less number of oxygen atoms. The number of the water molecules added should be equal to the number of the oxygen atoms short on either side of the reaction.

To balance Hydrogen:

Add Protons ()  where there are less number of hydrogen atoms. The number of the Protons added should be equal to the number of the hydrogen atoms short on either side of the reaction.

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.