Answer:
The answer is "no changes in oxidation number "
Step-by-step explanation:
Given equation:

- In the above-given equation, there are no changes in the oxidation number which can be defined as follows but first we defined the oxidation:
- In the chemical process, it requires the transfer of ions is oxidation. In particular, it means that products that supply electrodes are oxidized.
- In the given equation, when 3Potassium hydroxide reacts with phosphoric acid it will produce potassium phosphate and 3 moles of water.